This will document a load of random moments where characters in cutscenes T-Pose, or otherwise do things uncharacteristic off camera.
Final lowrider DLC cutscene celebration
The multiplayer characters can be seen clapping, presumably celebrating the end of a shoot for the lowrider DLC and one can be seen stepping off some sort of stage and going into a t pose.
i like to imagine the people that are being animation tracked or whatever the word is that they actually t-pose, which looks like what is happening due to the not so straight arms
They do in fact T Pose as that is a consistent pose that shows all the markers on their body so that they can properly setup the capture. They do it at the end as a reference point to help clean it up if neccasary iirc