Well, there are two other "solutions" if the engine bug can or will not be fixed (fixing bugs you did not create yourself can be very time consuming)
One solution would be to reset the flag, this might be frustrating if the flag could still be retrieved, but could not be abused.
The other would be to stop the flag.
Or... maybe just disallow flag tossing in general or something, have people play bomberball if they want to toss affinities. Might feel akward though and leave you with less options in difficult situations.
Or, last idea, reduce the momentum of flag tossing. This could be a server or mapspecific var (or just hardcoded) along the lines of "flagspeedmult" or something.
Of course, one could also do nothing about it, but I've tested it myself and I think it might get very confusing and hard to combat for new players if this tactic gets used against them. In general, the idea of giving the flag to your teammates is a good one imho, but with the current flagspeed it is just to easy to abuse/use.