@John_Mertic this was also brought up by @Brandon_Wick a bit ago in this post:
We found that searching for community members right now is best done by their username or email address linked with their account.
@John_Mertic The best workaround, for now, seems to be to search for users by email address.
@Nadia_Shomali thank you for logging this suggestion, could you let us know when this update gets pushed?