Ah okay.. I think I see the issue. On the phone recent page, the sim that the call was made from / came in from is shown to the right of the number, but you can only redial / return the call using the default sim... So example shown, missed call came in on my work Sim (orange) and I can only redial using my home sim (purple).. But. I've taken this one step further and tried to redial and I get the message that pops up checking which sim I want to use.. Very clever!!