If I try and boot while the TV is plugged in with the adapter, I get a black screen on everything and no signal on TV. I can have the dongle plugged in without the TV, it will boot but immediately cut to black when I plug in the TV.
This was all working the exact same way with my r9 390. I had originally bought these dongles to alleviate the lack of HDMI 2.0 on the 390 for my TV and VR.
Thanks for reaching out to us, I am sorry this is not working as expected.
I would like to start off by testing the graphics card with just one monitor attached to the DisplayPort output and booting to Windows to see if this behaves the same as with all the monitors attached. If the DisplayPort attached monitor and TV are both working, please connect the additional displays one at a time to the system and check for stability.
Please let me know if the DisplayPort to HDMI connected television works with just one other monitor connected to another DisplayPort output, and we can go from there.