After updating to the 21.20 update, my 955 asks to install a firmware update at least once per day, sometimes multiple times in a day. At first I thought it was incremental bug fixes, but now that it's been happing daily for so long I'm convinced it's some kind of bug.
I tried a "Reset > Delete Data and Reset Settings" and the issue still occurs.
Sofware Version Bundle: 21.20*
Host: 21.20
GPS: 12.00 Wif-Fi: 28.19
CIQ: 5.0.2
BMX: 18.1.6
WHR: 18.01.06
ANT/BLE/BR: 28.19
Wireless Status: 0
TSC: 1.14
Sensor Hub: 32.24
NFC: 3.4.8
WLT: 3.2.8