Hi, this is a bug and we are aware of it. You can see the open report on it here: https://community.gaijin.net/issues/p/warthunder/i/x3VxJlmAqf7H
Hi! We are looking into a way to help with this. We are going to make it so that if you have one modification that was fully researched and can be purchased for SL, then only one button for purchasing the modification for SL will be present. If you have no modifications that have been fully researched, then the Purchase all button for GE will remain.
Additionally, there is already a confirmation screen when clicking the buttons.