Can’t post in the OT thread, and can’t try with A4 now so, maybe a workaround…(working for OT)
Please test it!
I just found a workaround : 
Example test :
Trig 8 > pitch = 0, TRC = 50%, microtiming +23/384
Trig 9 > pitch = +12, TRC = /PRE
Trig 13 > pitch = 0
Slide trig on step 9
Enjoy conditional slides. 