Alright, I think I have tracked down the issue thanks to dedasdude's help.
Our tpucdn server wasnt properly configured to indicate when it sent a compressed or uncompressed response. So every proxy inbetween thought the response would be for both. When your browser asks for the compressed version now, the proxy in between returns the uncompressed, your browser tries to decompress it (which it can't), boom. failure
I fixed the setting on our side, now it will just take a bit of time for intermediate proxies to see the updated version from our server