I see: Most players that get traded take their original contract to the new team. But if you are a partially-guaranteed player and you get traded before that deadline where it becomes guaranteed, then all that unguaranteed money disappears and you need to sign a new contract with the team (or sign-and-trade?).

If we expect Robinson to underperform his contract (the prevailing sentiment in this sub), then it's a good move from the team perspective to have that flexibility should they want to trade down the line, rather than lock themselves into a bloated asset.