I am also affected by this bug. I compiled KMM from git master (commit 59be0db6; BUILD_WITH_QT6) on Debian Linux. The Debian KMM package based on release 5.2.1 is not affected. I could do a 'git bisect' if that was of help but compiling KMM on my laptop takes quite some time.
For me, the following workaround appears to stop the jumping. In Settings -> Ledger -> Display Tab -> Information headers select 'Show last reconciliation entry with date and balance in ledger' Before, the selection was 'Show all reconciliation entries with date and balance in ledger' which I guess is the default because I never changed that setting. -- Mark
