[hightech-guy]

Couple things likely occurring here...

First, the GM Ultium EV's will activate the EVSE outside of the preferred charging times for various reasons. You usually see this when you first plug in, even if you have scheduled / charge-later charging selected. Some of this is checking if the EVSE is ready to deliver power, in which case it clicks back off in a minute. But other times it will stay on for many minutes, starting at full power, and then trailing off to just hundreds of watts. This is a battery safety testing hold-over from the Bolt issue. Then there are other times that the unexpected wall power draw are not fully understood, such as OnStar comms with the mothership - and not wanting to sap range if plugged in and the car is awake doing things. The car also does more thermal management of things when plugged in and able to draw wall power.

Your other issue with the car charging now and delayed charging going away is likely due to how you plugged in. If you plug in and then unplug and replug (within a time window), the car will bypass the scheduled / charge-later setting and charge immediately. This is mentioned in the owners manual, and a way to force immediate charging without going into the settings. Has been this way on GM since the Volt. Sometimes you can also inadvertently trigger this, if you have some trouble inserting the charge cord.

This is all 'normal' for this car. What is abnormal with charging is that if the car sometimes forgets the home location and charge level. I don't think you have that somewhat common occurrence going on here, but just something to be aware of that sometimes you have to reset your home location, delete and re-enter scheduling, and re-set the charge target. Not often, but this is randomly reported - happens unexpectedly, and sometimes after a OTA or dealer update.