I'm not sure what you know or what all you've tried so I'm gonna put whatever I have out there. Apologies if it's redundant or patronizing. I really hope you get your problems figured out. RAM can be the most frustrating component in a build sometimes. I know all too well.
IME guarantees mean nothing. Some things can never really be guaranteed. 99% of JEDEC-certified RAM will work with 99% of mobos, but when you populate 4 slots, that percentage dips a little. Even QVL listed sticks sometimes don't work - I have seen it! The mobo isn't the only factor, there... sometimes certain CPUs just hate certain sticks. It could even be that the whole mobo/RAM/CPU combo is just not meant to be, yanno?
That aside, certain modules will just never work in certain boards in a 4-DIMM configuration, even if you can take any two (or any of the sticks alone) and have it work fine. Budget boards don't really help matters... the PCB quality and design matters. The higher your capacity, the greater the number of modules, or the snappier the timings/speed. Any one of those presents greater liklihood of failure or instability. The last two, especially. Honestly, I might've gone with 2 8's instead of 4 4's for that very reason. Something you may still want to consider.
4 DIMMS ask more of everything in the chain, from the board, to the controllers on your DIMMs, to the CPU/chipset controller... it's all being asked to do a lot more juggling, and that's really RAM in a nutshell... juggling delicate power states and impedance to sort rows/columns of data. They're sensitive. Things that ought to work don't always work how you like. Could be a million reasons. And maybe you can find them, but RAM isn't without its mysteries. It gets to the best of us.
Also worth considering... there can be huge variances within product families of RAM. Just as with any other line, not all Ballistix are created equal. Even the exact same kit can undergo revisions or part-swaps as needed. That's why you could buy a single stick now, and then next year buy another of the EXACT same SKU and have them not work together, whereas a pair of that same SKU bought at the same time would. The actual modules included could be from a different outfit (and even among the 3 main manufacturers, they have several different grades...) or maybe the controller is different. The performance characteristics and compatibility are not interchangeable like that... even boasting similar or even the same timings. It could still be completely different ram with different requirements under the heatsinks. The only thing you can usually be sure of is that the PCB will be the same.
How much is your BIOS config worth to you? My very first thought with this being an upgrade is to update the BIOS and thus revert to factory settings. Something about the fact that it will POST in safe mode and then actually run fine has me thinking it's somewhere in the current BIOS configuration. There's something to that. The fact that it's able to train and ultimately boot after a failed start is indicative of an unstable, non-stock configuration. What's probably happening is that it is attempting timings or voltages that don't work... just trying and trying. And then when you get into safe mode it's dropping down to timings that are much more likely to work no matter what. It's not getting over that hump.
I don't have a ton of experience with that platform, so grain of salt to what I'm saying, but a few nonspecific things come to mind. I know it seems counter-intuitive, but this is often how it is with RAM. Going from 2 lower capacity DIMMs to 4 higher capacity ones can get dicey. Yes, they should run at rated speeds and voltages, but sometimes you have to tweak it a little. It's impossible to account for everything. Sometimes it's a BIOS problem, which may or may not persist across revisions (sometimes newest versions even break certain RAM configs, with one a few revisions back being the best bet!) Other times it's a physical limitation of the board or CPU and simply can't be overcome.
I would probably mess with voltage a little. Usually, you won't need to unless manually overclocking, but it can't hurt to up your core memory voltage. I might also recommend upping VCCIO/VCCSA, or whatever your main controller voltage is in your BIOS. Sometimes with 4 modules it needs that in order to POST. Again, it's simply being taxed harder. Try little incremental bumps... just the smallest you can do, one or two baby steps at a time. And only a handful of steps max. If you're continually upping voltage with no results, something else is wrong. Start with your memory core voltage and if that doesn't work try upping the main board-side voltage. Maybe it'll help, maybe it won't. But it's an easy first step that takes just a little time. Just don't overdo it. It isn't without it's risk and past the necessary point, more can hurt stability, sending you in circles.
It may also be that your board, for whatever reason, can't handle running those particular sticks at the same speeds/timings as it would two, no matter the voltage. Less of an issue with newer Intel (especially XMP,) but still possible, as with any platform. With stuff like this, a little voltage nudge can still help get it there, though it's less likely to work. You may need to experiment with higher primary timings. Not ideal, but you could raise the CAS by one... or lower the speed by a stop.
I might also ask if you have XMP enabled. Those generally work fine, but not always. Just because a mobo has XMP capabilities doesn't guarantee that every profile for every compatible stick will work. It is pretty common for the exact same sticks to not run quiite as high bandwidth and/or low latency when running 4 as it will 2... especially when the capacity of the individual modules is higher (though in your case the capacity is still on the low end, so that would surprise me if it were true.) Usually the XMP will be set according to these things, but there are more things to go wrong.
That said, stock, non-XMP should always work with no fuss, assuming everything is in proper order. If a voltage kick doesn't help and they won't even POST with bone-stock timings, I would probably return them ASAP and try a different kit. Maybe you can get it to work, but not without heartache and performance loss. It's often not worth troubleshooting brand new RAM that doesn't work like it should, even if it is technically possible to work with it. Not worth it, IME and IMO. To me, RAM either works or it doesn't. The only thing that shouldn't reasonably be expected to work under normal circumstances is a full manual OC, especially in conjunction with an unlocked CPU, which isn't the case for you.
If there are no obvious reasons why it shouldn't work, but still doesn't, I don't bother asking why anymore. So much easier and often quicker to move on to another kit. Honestly, I'm leaning more towards that ultimately being what comes of this. That's just my hunch, though I do still think you should try to eliminate other factors... and maybe somebody will have your answer.
...could even be luck of the draw with that batch. Maybe one of the sticks is causing problems. Tried running just one or two at a time and swapping them out to see if they all work the same? You may just find that one of them is bad.
