Constantly get: Cannot make a cache safe URL for "15/0/1033/styles/corev15.css", file not found when

We're a 2 server MinRole farm, with Office Online Server, running SP2016 Enterprise on the latest security/cumulative updates. 

Almost every night, or every other night, this annoying issue keeps creeping back up, effectively making it impossible to open documents in Office Online Server:

Cannot make a cache safe URL for "15/0/1033/styles/corev15.css"

I have googled this issue and researched it as much as I can, to no avail. Corev15.cc exists in every location it needs to: which are:

C:\Program Files\Common Files\microsoft shared\Web Server Extensions\16\TEMPLATE\LAYOUTS\1033\STYLES

and

C:\Program Files\Common Files\microsoft shared\Web Server Extensions\16\TEMPLATE\LAYOUTS\1033\STYLES\Themable

This is not a custom style sheet obviously, and it's not a JS file that I forgot to put in a directory. 

Every time this issue comes up, I have to an IISRESET on both servers to 'fix' it, however it inevitably comes back in another night or two. In the interim I've had to schedule iisresets before working hours each day so that users are not effected by this.

We have modified the seattle.master file slightly(per site collection, not on the back-end), but I'm 100% sure this is not the culprit, as it's a system/farm wide problem, and I've created completely bone-stock, unmodified site collections where the master pages and all style files are untouched, to see if the behavior occurs on them and sure enough it does. 

We also do not use any other languages besides 1033 - English.

I was able to capture ULS logs from the correlation ID but they're unhelpful, to me at least, and I encourage anyone who is trying to help to look through them real quick. It's just from one correlation ID so it's not too many rows.

https://docs.google.com/spreadsheets/d/1rh-KuB3J3yB6DZCJmBXodg7AL9zEljPVKMDhlEvsKE4/edit?usp=sharing

Thank you in advance for any efforts.