Anyone contemplating returning the Mini should consider, that the FIX for this issue is on Intel, NOT Apple, and it's unknown if it's a firmware or hardware issue. Since June when this was discovered, Intel's two releases of Memory Resource Code (MRC 1.5, 1.6) have not fixed the issue, and it also affects the PC/Linux world, so it very well could be a hardware issue with the HD4000 iGPU.
My plan was to use the Mini as a desktop for a year or two, then migrate it to a HTPC, so having an HDMI issue is UNSAT, and I just called Apple for a RMA.