Automatic deletion of mail in Local trash bin

Am I doing something wrong? I have one account in Thunderbird that pop's emails from a Yahoo account. If I delete a message in Thunderbird it goes to a local trash bin and on default stays there forever. I want the emails to be deleted after 40 days in the trash bin. See picture. But it looks like it works exactly like it's described. Messages are deleted from the trash when it's 40 days after they were originally send. If I delete a message in the inbox older than 40 days it goes to the trash and is immediately deleted from it. I tried deleting several messages older than 40 days. The counter of the trash increases for a split second with 1. If I look in the trash the deleted message is not there. In my trash there are only messages "younger" than 40 days. At this moment the oldest is from December, 14 2025 Yes it works like the retention policy tells it should work. But this different from what I expect from trash folders Regards Ruud