Glitches with “Adjust display refresh rate to match video”

When I use “Adjust display refresh rate to match video”, I’m getting glitches a few seconds after starting a video.

I play a video, my TV screen blanks and then adjusts to the new refresh rate. Then, a couple of seconds later, it does it again – interrupting the video for a few seconds. If I turn off the setting, the screen doesn’t flicker – but, of course, some videos are a little juddery.

It’s like the Kodi is only detecting the FPS *after* it starts playing – if that makes sense?

I’ve tried playing with the settings which pause the video for a few seconds when a frame rate change is detected – but that didn’t seem to stop the problem.

My playback chain is: Asrock 330 ION running LibreELEC-Generic.x86_64-7.0.2 > HDMI > Onkyo Receiver > HDMI > Panasonic TV.

The Onkyo is set to pass-through the video signal without processing it. Similarly, the TV has all adjustments turned off.

Any idea how I fix this issue? Hopefully without buying new kit!