Headphone output impedance should be about ⅛ or less of the headphone impedance for transparent listening.
For example for a 160 ohm headphone would be ideally connected to a 20 ohm or lower impedance headphone output.
Recently I started having an issue where when starting video playback or maximizing or resizing a window playing a video on a 4K TV it would go black for a few moments (2-3 seconds) and then resume what it was doing. This TV has been used as a monitor for several years without issue up until recently. After attempting various fixes from rolling back drivers to disabling hardware acceleration I finally stumbled across a setting in the NVIDIA control panel that dynamically changes the content type reported to the display by default. By setting this to a static value, either Desktop programs or Full-screen video, the problem went away immediately. It appears that the problem was introduced by an update to the TV causing it to change image processing based on this value and temporarily render a black screen while the change was in action.