I am a new user of LibreOffice, just installed yesterday. Today I used it for the first time. I had two documents open which I;ll call A.docx and B.docx. A.docx was an older document that I opened use as a template for the new one. I opened it and said "save as B.docx". That was I still had the original A.docx, and a new copy called B.docx which I began to modify, doing occasional saves as I went along. Then at one point LibreOffice Writer just crashed on me - just as I was trying to hit Save again. When I restarted it asked me if I wanted to recover B.docx. 

When the recovery finished I clicked to open B.docx, and that's when things got weird. Both A.docx and B.docx opened up. Except that A.docx (which I had not modified at all) now contained all the data I had inputted to B.docx - at least up to the point at which I had last saved (not recently enough, alas). And B.docx appeared to be almost the plain vanilla original A.docx, except it also had a couple of the changes I had made to B.docx. As an example the two documents were minutes of meetings, and the A meeting was April 1 and the B meeting was May 6. I had changed B to May 6 when I began to make my mods, but had never touched A. Yet when A opened after the recovery it showed May 6 as it's date, and also had the data from B, and when B opened it also showed the date as May 6 and the opening paragraph from B, but otherwise contained the correct A data. 

To recover I had to completely delete B (since it was just a corrupted version of A) since I was able to download a new A from Google drive, and then had to rename A back to its correct name of B, and re-input all the data I had put in after my last save but prior to the crash. 

It was as if the two documents swapped their names and then also mashed some of their data together. so completely bizarre that I struggle to explain it. Sorry I didn't think to save the files to submit. I was just in a hurry to try to resolve. But now I'm hitting Save on my doc every 30 seconds!