Trunk-1.6 & chan_zap does not accept multiple calls

I have installed TE410P, idea is to accept incoming call from PSTN using ISDN PRI. it works fine with asterisk-branch-1.4 + libpri-branch + zaptel-branch. i have no issues with this combination. But when trying with asterisk-trunk + libpri-trunk + zaptel-branch, it doesn’t accept multiple call, only one call works fine. PSTN side gets all circuit busy and i don’t get anything on pri debug enabled mode. i think chan_zap is trying to use first channel always.

Here is my zaptel.conf

span=1,1,0,ccs,hdb3
bchan=1-15,17-31
dchan=16
loadzone = us
defaultzone = us

zapata.conf

[channels]
language=en
group=0,11
context=from-pstn
switchtype = national
signalling = pri_cpe
channel => 1-15,17-31
group=
context=default