Hi there! It's pretty common for me to set a optional runway in sim brief, generate the fight, then import into P2A, but have P2A insist on its own runway. It seems odd that P2A ignores the runway I set in simbrief. Am I missing anything?

Make sure the "Import Procedures" option is checked on the Import panel and that you have set a procedure, like an ILS or RNAV approach, to the desired runway.  P2A will then import that procedure and select that runway, as long as you have the ATC Assigns Approach and ATC Assigns STAR options turned off in the P2A Settings->FltPlan tab.

Dave