On Rec2 Window there are two settings Fade In and Fade Out.
Set them to the lowest setting (above zero) of 0.63 to achieve a click-free looping recording with a trig-based two bar recording. [or however many bars the user chooses].
Pro Tip: The settings of Fin and Fout will be remembered - not by the Bank, nor by the Pattern, but rather by the Part.
So if the Part is changed from 1 to Part 2, the Fin and Fout will then need to be again set to that lowest setting (or whatever setting the user chooses). It isn’t all that inconvenient as there are only four parts.
But the trick is to understand the Rec2 settings are Part-based. Not a global setting, so when a new Part is selected, it’s default Fade In and Fade Out will be at zero, and therefore there will be a click sound at the start and end of a realtime loop recording. Set Fin and Fout to 0.63, no more click.