I'm not sure if this is a bug or missing feature, but on tv shows streaming from Yatse via UPNP, it doesn't send a seek to the resume time when selecting play and choosing the resume. Playing to UPNP on a mirascreen device that does support seek as I can manually seek by sliding the timeline slider. If seek is implemented, it is possible the seek is sent before the upnp media is loaded and ready to accept the seek.
Yatse does resume but I guess yes the resume goes to early problem is that some devices does say they are ready when they are not and accept the resume command even if they do not seek.
For those device it's quite complicated to handle things.