[tjost]

Maybe thats the same issue some of us see when watching livetv with USB TV cards. Here the issues also increase when copying files to le samba shares during watching.
This issue started with kernel 4.9 and isn't solved until a year now.

and the 4.9 Kernel isn't in LibreELEC 8?
Shame on this Kernel.
Until now the Builds from Milhouse are stable but I recognize a few lags. Hope I´ll fix. 
Back to LibreELEC 8 is not an option Milhouse made a patch just for me in 127 of LE9.