Can't assign keyword to a group of photos in Bridge 2024

Dear all,

I selected a group of photos under Bridge 2024 and tried to assign a common keyword to all of them.  However, the keyword was only assigned to the first photo but not the rest, and when I closed the Bridge and reopened it, the assigned keyword just disappeared.  I tried purging the cache but it didn't help.  What can I do?  Thank you.