I've seen this and since one worked and the other did not (HDMI wireless) I chalked it up to the HDMI wireless and not the PC. Some of them are iffy barely working devices.
Also, I've seen this when the projector was not really 1080p. Let's get the model numbers of the projector and HDMI Wireless system in this discussion next.
I am having an issue with my wireless HDMI to my projector. When viewing through Dish network receiver I have a full 1080 picture. When I switch to my computer for the display, the signal cuts in an out about every 2 seconds. I have just about tried everything I can think of. My PC has an onboard Intel HDMI out, I also have a GeForce gtx 1060 graphics card. I have updated drivers for both, used different cables and still have the same result. When I connect a smart TV as a display for the computer, it works perfectly. I have gone as far as using a VGA to HDMI adapter. This worked for awhile, but now it cuts out. My thoughts are the refresh rate needs to be below 60hz but the options I'm given for either outputs don't give me that option. I'm guessing the signal from the PC is in a format the wireless transmitter has a hard time recognizing, at least at the speed it is sending. Any thoughts?