Yes, I have this problem too.
Simply put, I have a .mkv-file where the soundtrack is 6-channel (5.1) LPCM. When playing it, the channels are wrong - like the center channel is played through the left rear channel.
I've tried to find a solution for this, but searching only reveals that this has apparantly been a problem for more than a decade, and on all platforms.
I'm running VLC 3.0.8 on Linux Mint, and all other surround formats plays perfectly - only LPCM is screwed up!
My sound output device is set to "HDA Intel PCH, HDMI 0 Direct hardware device without any conversions". In Audio -> Output modules -> ALSA, Speaker configuration is set to "Surround 7.1", even though I have only 5.1 speakers - if I set it to 5.1, the center channel is completely muted...
Is there any soultion to this? If so, how?