Just set Defectors to automatically teleport toward the group if they get too far away from other units.

[(XBOX)TehChubbyDugan]

It's been years since defection came out.  DE refuses to fix their mistakes and AI issues with the entire reason people hate this game mode.  Defectors gets stuck, them getting stuck prevents the game from counting a squad as rescued, and you either have to abort or wait for them to hopefully die, which also counts against you.  

There is no reason for this to still be an issue.  Especially when it's literally the same exact spawn points over and over where they get stuck.  There is no reason for fail states to be linked to issues that rest solely on the developer and not the player.

Remove the tiles where they routinely get stuck, and set strays to teleport back to the group if they get too far away from it.  Any "balance" issues that anyone thinks would arise from this are moot.  We've dealt with this buggy mess for too long.