Weird problem with YSF on duplex MMDVM Hotspot

[2E0PJY]

Hello all

This is really got me totally stumped so I would be grateful for any pointers from this knowledgeable group!

I have a duplex MMDVM Chinese clone board, running on a PI4 using the latest software and updates, I have flashed the modem and it works absolutely great on DMR. I have YSF enabled also but that doesnt work so well, the problem I have is as follows (excuse my explanation!).

When I make a transmission linked to any reflector or room, upon releasing the PTT I receive a short (approx half a second) retransmission of my signal. I have tried this by using the parrot and it works like this:

PTT pressed, say a message and then release the PTT. Almost immediately from unkeying I receive a quick burst of the message which then also unkeys. I then receive the full message retransmitted to me. I thought initially it was some form of standby bleep or tail transmission but checking it on another radio it receives the same.

Sorry if this is unclear and I wonder if its anything to do with the fact that I am using a duplex board but I have tried everything to rectify without success. BER fluctuates but is between 0.8 - 1.2% and I am using DMR, YSF, and YSF2DMR, YSF2P25 and YSF2NXDN via DMRGATEWAY.

Any help would be appreciated!

73