How to get swipe release coordinates using tch0-3

Hello all,
First post here.
I’m using v1.63.3 to try and create swipe actions directly on a 3.5" Enhanced.
Reading the instruction set doc (NIS) suggests that tch0,1 coordinates are set when touch starts (swipe start), and tch2,3 are set where and when touch is released (swipe end).
This doesn’t seem to happen in practice.
What I’m actually seeing is tch2,3 being set to the start coordinates at touch start, and NOT updated on release.
However, the setting of tch0,1 to the touch start coords, and then to zero on release, does happen.
This behaviour is the same in the debugger AND the actual panel.
Is this me not understanding the documentation (likely), a broken panel, or a bug (unlikely)?
What is the correct way to do this?
Thanks.

Edit:
After more investigation, it seem that sendxy=1 also doesn’t work properly for me.
It only sends coords at press and release, nothing in between.
Also, the release coords are still the start ones, not the release ones.

Perhaps this panel is too old?
NX4832K035_011R with ITEAD logo.