This is an issue that I have seen in previous versions and have reported to Adobe support personnel before. I've noticed it again in 2023 (Build 63), Windows 11 (latest updates).
When I enter keywords in the description field of a clip that is in a bin I can subsequently search on those keyword by tpying them into "Filter Bin Content" field. This works just as it should. I can also take a sequence into the source window, cut clips from it, drop them into a bin and add keywords to the description field. However, when you use the "Filter Bin Content" field to search these clips no results will be returned regardless of what text you enter.
This has worked in prior versions and is a bug. I am sure that myself and many other users cutting mutlicamera nested clips (sequences) would appreciate this being fixed. I am willing to demonstrate the issue via screen recording if helpful and necessary.