htp and cross ICBF

hi
I creative a scene is a desk ch
and I change it to cross ICBF. let me can control it at fader.
but I got a problem is about htp.. because I like to make this scene be htp.
but if I change to use htp and run for a while it will be full and I can't release that..until I deselect use htp and the will be normal..
after I get this problem..if I creative a same desk ch de a list and make it be cross ICBF and use htp:) same problem will happen again.
that is mean if a list or scene can't work in HTP and cross ICBF.
I try some step to creative .any list and scene after use htp and cross ICBF
will be full automaticly..
it is a bug or wrong operating?

1.2.1
NANO
RH4