Audio doesn't match video - several players

Hi. For some time I have a problem which can't be caused by anything else but the codecs - the audio channel runs 2 seconds slower than the video channel: for instance, if the character starts shooting with a machine gun, I can see them doing it and 2 seconds later or so I can hear the sound of the machine gun. Currently I'm watching a tv show which didn't have this problem on December last year when I watched it for the first time. And that problem can be fixed only temporarily if I restart the player and in about 10 minutes the audio channel becomes slower again. I use KMPlayer but I also tried with a few others - GOM, BS, POT, WMP.
If you have any suggestions how to fix that problem? This sound problem started since I installed K-Lite Mega 12.15 and it persists in 12.22. I couldn't find any older versions of K-Lite (at least not without adware attached to them). I'm thinking that installing an older version from December or November 2015, it will work fine. As I said when I saw that tv show for the first time, there was no problem with matching audio and video AND the media player was the same brand and version - KM Player.

There are more than a million people using the last two versions, and so far you are the only one that has reported this problem. So it is unlikely the codecs, at least not with default settings. Check the settings of LAV Audio decoder to see if the audio delay option is enabled. Should not be unless you enabled it yourself.

KMPlayer (and also POT and GOM) uses its own codecs by default. So check which filters it uses. There should be a list in its play menu during playback.

I am assuming you are playing on a computer monitor, and not on a TV or with a receiver for your sound system?

Are you using a custom audio renderer such as ReClock? That also has an audio delay option.

I also suggest re-installing your audio driver.

I haven't changed any codecs settings because I don't know how to do that. The only setting I've made was in KMP itself, forcing it to use K-Lite codecs because its default codecs suck.
My monitor supports HDMI Audio but I never installed the driver for it, not to mention I've disabled that function in Windows control panel. I also don't know what ReClock is - never heard of it.
I'll try reinstalling the audio driver although I doubt that will fix anything.

Does it also happen with Media Player Classic?

MPC-HC menu > Play > Filters
Should look like this:

Filters currently loaded:
- Default DirectSound Device
- Enhanced Video Renderer (custom presenter)
- Audio Switcher
- LAV Video Decoder
- LAV Audio Decoder
- LAV Splitter Source

If the delay is a constant 2 seconds, then you could set audio delay in LAV Audio decoder to -2000 ms.

At this moment I don't know what causes your problem.