Using Yoda's command card [There is no Try], Yoda can give the Relentless keyword to another unit.
For this example, lets assume the second unit is a unit of Phase II Clones with a Mortar, with the Cumbersome weapon keyword
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During Yoda's activation, he uses the Guidance action to move the Phase II Clones, causing them to move. A move will trigger Relentless. Can the Phase II Clones attack with their Cumbersome heavy weapon? Both the movement and attack would happen during the same activation, Yoda's. Current Cumbersome rules (Emphasis mine)
> A unit that has a weapon with the Cumbersome keyword cannot perform a move prior to performing an attack using that weapon during the same activation unless the move is a pivot.
In older rules, Cumbersome was limited to during the activation of the unit with the Cumbersome weapon. This allowed this interaction to function
Old Cumbersome (Emphasis mine)
> If a unit performs an attack with a weapon that has the cumbersome keyword during its activation, it cannot perform any moves during that activation, except for pivots.
This question boils down to "Does Cumbersome care about who's activation it is, or just that both the move and attack happen during the same activation at all?"