Running 25.9 on the AP's. All the AP's are plugged into MS Switches running 9.34.
Happens across multiple sites.
iPhones are roaming trouble free. Not saying it isn't the Cisco handsets, and they are known to have issues, just seeing if there are others having trouble as well.
Have had Meraki support look at it multiple times, and they blame the handset. Haven't bothered with a Cisco TAC yet.