I discovered this behavior over the weekend. Included is a photo as it occurred on iPhone but I first noticed it on iPad. Version is 25.3.2.
When selecting a spot and then adding a second operator callsign, a number entered gets inserted into the first callsign. It seems to happen regardless of the initial callsign but only when the second callsign being entered is a 2x, such as KB3… It seems very repeatable but only happens after selecting a spot not when entering the initial call manually.