PMP audio distorsion issues

Hello,

Configuration:
PMP 2.6.0
Windows 10 x64 (1607) running on Intel NUC6i5SYH
NUC connected to Denon AVR-X2200W by HDMI.
Speakers: Dali 7.1 set (2x Zensor 7, 2x Zensor 1, 2x Alteco, Vocal, Sub E-9F)

I’ve been using Plex for almost 2 years, mostly without major problems. But since ab. 1-2 months I’m facing with strange audio issues. When playing movie, I can hear a frequent 1-second distorsion. Sometimes it is just a short “mute” - no audio. It is hard to tell the interval, but it seems to be non-regular. But often, like every 2-3 minutes.
I’ve tried may configuration options, but none eliminates the issue.
I’m playing movies in original format (no transcoding) with audio track DTS 5.1 (mostly), AC5.1 or DTS 7.1. Issue occurs regardless of the audio format.

Important remark: when playing the same movie using VLC, there are NO audio distorsions.

The PMP configuration file in the attachement.

Your help will be a very appreciated.