My original post showed that the negative values were in both files to go and bytes. I’ve tested what you suggested. With a single 1GB file, I see this:
Interestingly, if I create 5 1GB files, it seems to be counting the “files to go” down from zero:
(above is captured in progress, it finished at -4).
The lastPgEvent had this value during part of the above process:
{
"BackupID": "26",
"TaskID": 21,
"BackendAction": "List",
"BackendPath": null,
"BackendFileSize": -1,
"BackendFileProgress": 3749,
"BackendSpeed": -1,
"BackendIsBlocking": true,
"CurrentFilename": null,
"CurrentFilesize": 0,
"CurrentFileoffset": 0,
"CurrentFilecomplete": false,
"Phase": "Vacuum_Running",
"OverallProgress": 0,
"ProcessedFileCount": 5,
"ProcessedFileSize": 5368709120,
"TotalFileCount": 5,
"TotalFileSize": 5368709120,
"StillCounting": false
}