Yes, I'm having some pretty annoying bluetooth issues with my 2015 200C with Uconnect 8.4. The device will pair fine and music will be playing and suddenly the whole thing just freezes. The phone drops the connection and *deletes* the UConnect Bluetooth connection. UConnect in the car will freeze up thinking it's still connected to the phone, I can still get to Sirius/XM, but the connected media functionality is dead. I'll shut off the car and then have to re-pair the phone upon restarting the vehicle to get the phone to recognize it again.
I've never seen any issues before with my Note 4, G4, G5 or S7Edge. Shame too, because audio quality is significantly better over bluetooth than any previous phone I've had. I hope Google fixes this one quick.
Edit - I just updated UConnect to the latest version for my car v16.16.something from April. It was previously on a version from late last year. I'll see if it helps at all, but I still suspect that it's a Pixel issue.