My ultra s21 is doing the same note 10 glitch... So I have 2 sims, both data on; in UAE which uses etisalat...
Sim 1 etisalat
Sim 2 Google fi
I set sim 1 for calls + messages + data and nothing for sim 2... 15 minutes later, you will realize that the phone chose sim 2 for data without my input... Glitch
I set a data limit on sim 2 of 1mb... Gave me a warning that I exceeded the limit and still uses 4 or 5g on sim 2 ????? Glitch
I turned off sim2 completely, now the new glitch is when I go to the garage (data, sms, calls on sim1) the phone loses connecting, which is understandable, but when you exit the garage and the phone reconnects to a gsm network, all works except data, I have to go into the settings and chose from nothing to data on sim1, the other option is sim1 data off.... I don't know why it empty, nothing is chosen... After flipping out again data to sim 1, Then it will work again... GLITCH.
It happens almost everytime, I contacted samsung, they said we can't help you.
I switched sims around, same thing.
Ummm anyone with the same problem?
My note 10 did the same exact thing, but my xperia 2 and xperia 1 didn't have those issue.
Look at the picture, glitch 3 after I connected to WiFi, once I disconnected WiFi, it went with data not chosen sim1 or off its just empty..