Audio HDMI passthrough not working above 1.5.4.8

Sorry for my bad English.
I have problem with audio HDMI passthrough on fresh install K-Lite Mega Codec above 1.5.4.8. 1.5.4.8 is lattest version then HDMI passthrough works. Off corse in all above version i check hdmi passthrough but not working - then on my LCD ampituner is STEREO. When I install fresh version 1.5.4.8 and then the newest then all is working.
Why doesn't work in fresh install of newest version K-Lite ?

Thanks,
Thomas

Most likely the correct audio device is not set as the default one in the Windows sound settings.

Otherwise disable "Fallback to PCM if bitstreaming is not supported" option in LAV Audio decoder.

Ok. It is working now but in previous version this option is enabled on deffault and HDMI passthrough is working. Strange.
When I install 1.5.4.8 and then the newest version is working too with enabled "Fallback to PCM...".
Only then I fresh install above 1.5.4.8 the I must disable "Fallback to PCM...".
Thanks.

Check what is different here:
MPC menu > Play > Filters

Maybe it is because of internal audio renderer?

No. Always LAV Audio Decoder.

Decoder and renderer are two different things. The output of the decoder goes into the renderer.

The internal audio renderer was not used by default in the past. You can change the renderer here:
Options > Playback > Output