I used spamsieve for years on High Sierra without problems.
I upgraded to Monteray and reinstalled spamsieve as per the instructions. All is working but statistics shows 102 good and 63 spam.
WHERE ARE THEY?
All Junk has 1 message in it.
There is no sign of the other
Which section of the Statistics window are those numbers from?
Please check your SpamSieve rule in Mail’s preferences. Which mailbox is it set to move the messages to?
Also, please make sure that each account is set to store its Junk mailbox on the server, as described here.