Hi @smidsrw
Welcome to the Sonos Community!
Sorry to hear about this issue you are having with certain speakers not grouping together.
Such issues are usually caused by a firmware version mismatch between the two speakers. I recommend you check your system for available updates: Settings Icon » General Settings » System Update » Check for Updates.
If this does not fix your issue, I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.
I hope this helps.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein