Your setup is not common, and that fact alone would make it unlikely to encounter someone with the same problem.
I have to assume, since you didn't provide any details, that you have a non-reference card with two DVI, one HDMI, and one DP connectors.
You can only use two out of the first three at the same time. Normally, you'd be able to choose which one to disable, but I'd guess that the unpowered HDMI connection leaves the card and/or the driver stuck waiting for information.
Best suggestion I can make is to give feedback on the drivers to AMD.