Hm. Actually yes, I think this mess started after I updated nixos on my laptop (which updated signal-desktop) and that's where I saw this weird notification. It said I had to update the software on my 'original device.' I had originally installed Signal on my old phone, but then transferred the account to my new (grapheneOS) a while ago. It gets too messy and complicated to explain from there. Suffice it to say, this is probably my fault.

I use Molly on two different profiles on graphene os. Molly is always behind Signal by a bit. Maybe the update to signal desktop on the laptop put it 'out of reach' for the Molly versions on my phone.

Guess it'll be quiet for a few days while I wait and see...