Tvheadend

When watching only HD or SD channels working fine. When changing from HD to SD channel working fine also, but after changing from SD to HD channel buffering time is long and after that only HD channel audio working, freezed picture from earlier SD channel left on screen.

Playback have to be stopped, and after that HD channels working again.

Any suggestions how to fix this?

TVH 4.0.10 (Tested TVH 4.1.2286. Same thing)
KODI PVR-TVHeadend HTSP Client 2.2.15
Raspberry Pi 3 (with MPEG2-Licence)
Sundtek SkyTV Ultimate 8 2018 (DVB-S/S2/S2X)-Stick.