Asterisk 13.2 Video H264 does not work properly


I have 2 asterisk boxes (100% identical, and both compiled locally), one is running asterisk 12.8.1 and the second asterisk 13.2
I am trying to roll out asterisk to production, the asterisk 12.8.1 is having issues when linking it to a pbx running asterisk (yeastar Mypbx U200) using IAX2 trunk. The voice quality is very bad.

The asterisk 13.2 is working perfectly fine on IAX2 however the the video H264 is not.
My devices are Grandstream GXV3175 and GXV3275 and Mobotix Q24 as well as acrobitz groundwire softphone

I seek someone’s help to fix one of the 2 asterisk versions.
the 12.8.1 H264 works perfectly but the IAX2 trunk quality is very bad although I tried all codecs possible. (I cannot use sip trunk with Yeastar U200, it works one way dial, and they do not give us the permission to change any config file)
The 13.2 IAX2 works perfectly on any codec I use. However the H264 from the GXV3175 towards the GXV3275 is very smooth but from the GXV3275 to GXV3175 is very lagging maybe 1 frame per 10 seconds. the same with my mobotix video is extremely slow on the grandstream devices as well as on my acrobitz groundwire softphone.

I made lots of researches on asterisk version 12 (many places mention about the IAX2 voice problem), as for the asterisk 13.2 being recently released there is no much posts about it, it could be worthwhile verifying the format_h264 code on asterisk 13.2.

Unfortunately I cannot use lower asterisk versions since I have my webrtc already working fine on both versions 12 and 13.

Thank you in advance for your help.