Using the "Transfer Fleet" button in the Naval Organization window with a fleet selected, Miscellaneous tab throws an error: "2.0.3 Function #3397: Object reference not set to an instance of an object."
Tested on a fresh DB with two player races on Earth and incremented 5 seconds before transferring. Error occurs when transferring a fleet from Race B to Race A, and when transferring back from Race A to Race B.
Game seems to otherwise work fine.
EDIT: I notice that the game creates copies of the class design named "ClassName - Copy" (and keeps appending " - Copy"s if you transfer back and forth), with alien components displayed in red (so shown in red for Race A, but not for Race B, in the example above). Could this have something to do with it?
SJW: Fixed for v2.1.1. The error was caused by the code assuming the destination race was an NPR. The error will have no effect on the transfer.