Tvheadend

You should provide a more detailed description of what's happening, what source you are using and how everything is configured. Also you could try using for example VLC Player as client.

It's probably UDP packet loss. TVH does not do any bandwidth control, so the UDP packets are pushed in chunks to the kernel stack. It looks like that those untuned consumer devices have trouble to grab all packets from the network.

UDP? I guess tvh use tcp?
And by the way, i have the same problem with a panasonic nad tvh, but minisatip works like much better.
At the moment i try to create a m3u list from tvh for a automatic import to minisatip.

The standard SAT>IP transfer method is RTP/AVP/UDP. The RTP/AVP/TCP extension is not in the standard. I do not think that the consumer devices will support the TCP transfer method. Minisatip does less buffering than tvh, thus the data are usually sent in the smaller chunks, so the local network can handle this with less drops.