Well, after adding the license it really works. Although does not explain why channels doesn’t work after changing back and forth channels. License is kinda commercial workaround.
Btw, I added exactly this same question to openelec boards. Not a single answer.
So thanks for your trobleshooting help.
Still don’t know is this kodi, tvheadend or osmc bug but atleast channel jumping is a joy again 
Edit: btw this si2168 dvb dongle works only after addin drvers manually like in the post linked, altough should be supported in osmc, otherwise dvb-t channel scan fails at tvheadend