Problem with MLS Transfers

I offered out one of my players to the other MLS teams for a dp slot, got a few offers in return all which offered 2 years dp slot in return for the player. I didn't touch the offer and was happy to accept, went to the bottom right and rather than accept it said "Negotiate off" dispite the fact I hadn't made any changes. I thought it was normal, sent the offer back hoping i'd accepted and the other club withdrew their offer as if i'd asked for some ridiculous amount or a slot for 5 years.

Anyone know why this happens? It happens on every transfer negotiation for a dp slot. I've tried negotiating down to a 1 year slot and they still refuse. I'm playing on 10.3 with a custom database with transfers, don't know if that's affected it?