After Effects file won't save when AEP gets to 2GB in size

I'm absolutely gutted, I just lost a whole day's work with a following day deadline....

I was working away using RotoBrush which must save all its frozen rotos into the AEP which results in a bloated file. Unbeknownst to me, since there were no errors or warnings, none of my saves actually saved, nor did the auto saves. I only found this out when i went to upload my AEP to send it off to the client, I noticed the "Date Modified" was from this morning, only a few hours after I started working on the project! Same with the autosaves. I went into the recycle bin of my Synology NAS and I found all these temp AEP saves and auto save files all with the same file size in increments of time all through the day until I stopped working, meaning it was trying to save and created a temp file but gave up with no warning (see attached image) The file size being around 2,175,221KB (2.07GB) for every file. When I try opening these up, I get the "After Effects error: missing data in file ( 33 :: 4)".  Same when I try to import it into a new project.  Either it's a weird coincidence that the file stopped saving once it hit 2GB or something else was at play. But why was there no error message when I manually hit save and during autosaves? I'm incredibly frustrated and disappointed and have screwed over a client...  Thanks Adobe!