HDMI glitching

Hey.
I just recently bought a BBB wireless, and I’m experiencing some glitches when connecting it to a display.
I’ve installed the latest image, and updated as shown in the guide.
The weird thing is, it seems like the display is stable during boot, and the glitching only starts after it has fully booted.
The glitching looks like random “noise” on the display, and random quick blankings.
I’ve tried with different screens: my main monitor (Dell 24" screen"), a small waveshare 4.3" lcd, and a 7" 1024x600 rpi display. All show the exact same glitching. I’ve also tried different cables, which makes no difference.
Is this just to be expected, or is it something I might be able to do something about?

Regards
Anders