This document contains unknown data which will be discarded to keep layers editable CC 2018

Hey, I'm getting an error when I open a particular psd in CC 2018, stating

If I click keep layers, photoshop loads the file, but still flattens it anyways. I've tried to open the file on Windows 10 and MacOS, and in CC 2018 and CC 2014, with no avail. Since the file was saved on a usb, I can't seem to use Window's previous version to try to recover the file that way. I used a file recovery program to recover a previous version of the file, but unfortunately cannot open it, getting the error " Could not complete your request because it is not a valid Photoshop document." I've also tried resetting photoshop preferences and reinstalling Photoshop CC 2018, but no hope there either. The file is decently large, being 1.66 gb, however another psd I was working on at the same time and in the same session, which is also around the same size, received the error when being opened, yet it was able to actually keep it's layers. As the work was for a customer with a due date, would suck if I would have to redo the artwork for the file, so I'm willing to try any suggestions the adobe community may have!

Thanks