Searching within a message using slash fails the first time

(If this is a duplicate, please feel free to delete. I posted last night, but the question appears to have vanished from the forum.) I'm using Thunderbird 151.0.1. After 151.0.0 was installed, the ability to press "/" ("slash") to search while viewing a message was broken. The slash is ignored, and following keystrokes are then acted upon. If a search is initiated by pressing Ctrl+F, subsequent searches can be started with a slash. It's only when the first search is done that the slash is ignored. I've been using Thunderbird since the beginning, so starting a search with a slash is in my muscle memory. As a result, I've inadvertently marked or archived or starred messages, navigated to the next thread or next unread message, etc. Looking at the release notes, I see that a search function was fixed in 151.0.0. I wonder if this is related to that fix? In any event, can "press slash to start a search in the message window" be restored? ...thanks!