Mission Psych00 should only be valid if the player has not already encountered Psych01. However in several 1.9b4 games I have encountered it afterwards. The problem is in Psych01 which calls msnSuccess from within the OnAccepted event - as such the mission is completed BEFORE the mission is considered an active player mission and therefore it is closed as a non-player mission (final status will be success rather than playerSuccess) and the mission object will then be deleted when the player changes system.

Can resolve by adding recordNonPlayer="true" to Psych01