I have no experience with spousal benefits, but can comment on SSA/FBU "surprises". Without going into the details (they are described in other threads), I've encountered nothing but surprises and poor communication from the FBU and SSA since April 2022. I'll just tell you the most recent one.
Last month, I realised I had not been paid my SSA retirement benefit. No letter in the mail, no messages in my SSA account, just no payment for January. I eventually found out that my payments had been "suspended" for not submitting a particular form (7162) in 2024. The thing is, I HAD submitted the form in 2024 (twice!), and had delivery confirmation records for both occasions. So, I duly filled in the relevant form AGAIN, and sent it with copies of the same form from the two previous occasions, copies of the delivery receipts for the two previous occasions, an appeal form (SSA-561-U2) and a brief cover letter. I sent all of this to FBU AND sent it all to SSA in the US.
I received confirmation of delivery to FBU on 11th February. Today, on a whim, I decided to log into MySSA account. Lo and behold, my payments have been reinstated for this month - but no indication of what is being done about the incorrectly suspended payment for January.
From my experiences over the past 3 years, their errors do have a habit of rectifying themselves, eventually, but usually without any letter or message explaining what the heck was going on. Frustrating, but I've learned to always give it a little time before I blow a gasket. ;-)