I charge both my EVs from excess solar nearly all the time. When I do, the EVSE continually changes the Pilot signal (which signifies the max Amps). The car faithfully follows this max Pilot (I monitor on TeslaMate). However, if I have the Tesla App open at the same time, something goes wrong and the charging level goes all over the place. It looks like the phone App is fighting the EVSE. So, I always charge using excess solar with the Tesla App well and truly OFF. However, if I set the Pilot level in the EVSE to a fixed value, the car and App both behave sensibly and charge at that level but allow me to decrease the amps below the EVSE setting either from the car or from the App..
Not sure if this helps you.....