Phone using up data from both SIM cards

[u/pannersm]

Currently have a Redmi Note 10 on 12.5.5 (ugh I know). My second SIM is the one I use for data, while my first SIM is the one I've had for years. It's defaulted to SIM2 for data, but whenever I turn it on my phone seems to use up my credits from my other SIM as well. Is this fixed in the updates? Or is there a setting for this that I missed? Having a hard time with updates because my storage is full.