The target SoC for my MG4 gets set to 90% after every restart of the SAIC MQTT Gateway (Python) HA add-on.
Regardless of the current setting (I have it normally set to 80%), simply restarting the HA add-on will reset the target SoC to 90%. Same happens obviously if HA is restarted.
I'm running v0.9.8 of the add-on.