Scan " Start Fresh", is not working with Brother MFC8690 - Scan multiPage in one File

[Goemsinfo]

Hi,
When i'm scanning, with option enabled " Start fresh" ( target : 1 page scanned by feeder = 1 PDF file output) , is not working. they scan as a PDF multipage.
On Workarround ,o option to "split" this "multipage PDF" in "multi PDF file"

Tested on HP 477, and that working fine.
Things strange , it worked like a charm with the brother 2 weeks ago. I tested now on a new computer ( fresh install) and get the same issue.
Second thing strange, by testing multiple times ( no change of configuration, of number of page scanned), it worked 1 times on 10 test, i cannot explain why.

When it's working, on each page feeded, we need to click on "SCAN"

Bellow the screenshoot and log of scanned page failed ( 2 pages -> 1 PDF)

Expected behavior

Screenshots

Log data

log20230331.txt

Thanks a lot
Simon