I'm using Lightroom 8.1 on Windows 10 1809. I've chosen to always get prompted about backing up the catalog when exiting, but after I upgraded to 8.1 (from Lr 8.0 on Windows 8.1), it seems that something goes wrong when backing up. Every backup now includes the lrcat-wal (sql lite temp file) and the unzipped version of the lrcat file. Size has blown up from 200MB to around 1.0G for each backup, and it takes a lot of time to exit.
Does anyone else have the same experience? I will probably file a bug report with Adobe, but it would be nice to know if I might have triggered this behavior by some commonly known issue.
My current workaround is to not open a default catalog and check the checkbox for testing catalog integrity when opening Lightroom and then use a powershell script to start Lightroom and then do a backup of the catalog with the Compress-Archive cmdlet after exiting. In addition, I must remember to optimize my catalog manually from time to time. I think that would keep my catalog safe enough, but it would be better if everything worked as expected.