Strange Issue when Using Iframe API

I had an strange issue when using Iframe API when udp is blocked.
Say there are three participants in a conference A, B and C. A and B resides can use both TCP and UDP for the call. C is inside a TCP only network.
Some times the video or audio does not work for C. Both remote host and port are shown as undefined for C. But when C joins from the Jitsi Meet itself, without iframe. It starts working. Has anyone faced a similar issue before ?