Clubs can include clauses in transfer agreements that prevent a player from playing against their former club during a specific period, often referred to as a “gentleman’s agreement” or a formal non-compete clause for specific matches. This is especially common when the transfer occurs mid-season. 

If the player only had few games left on their contract, the selling club might use this clause as a negotiation point, especially if the transfer benefits both clubs and the player.

So, @KeralaBlasters and @OdishaFC might have mutually agreed on this. Otherwise, it would be a poor decision by KBFC.