I encountered such errors when I make an internal call between 2 yate client SIP softphones:

rtpengine is used and no audio:

Jun 19 10:02:35 kazootest2 rtpengine[2066]: [918508371@kazootest2.siplabs.local port 30942] Error parsing RTP header: short packet (header)

when I turn off the rtpengine:

THe Freeswitch handles such RTP packets correctly and audio is ok.

I compared manually rtp packets from Yate: they comply to the RTP specification.

2) A call from WS client(jssip) to an ordinary sip softphone:

Jun 19 09:58:36 kazootest2 rtpengine[2066]: [s2m2k70tu0d12bjnnamr port 30814] Error parsing RTP header: invalid header version

How to fix these errors?

The rtpengine looks through all incoming packets while looking for a new RTP stream. May be packets parsing is too strict?