@Mention works inconsistently

@Mention lets us mention another member of the community to provide a contextual reference to that member's bio and other information.

Sometime in 2023 Be Communities changed the @Mention feature. It's supposed to be enhanced, but doesn't work.  Here's an example...

I want to mention Bentley staffer Robert Hook in a post, so I start to type @R and see this options panel pop up...

Mention Default

I carry on typing Robert's name and the panel changes...

Mention Other Members

I choose Other Members but Robert's name does not appear in that list. 

I type more of his name and the panel changes again...

Mention Other Content

But still no Robert Hook.

I find the @Mention feature broken.  I can no longer use this very useful magic.