The bug is you can't remove the Misc. Mod from the armor, all you can do is replace it. You can find Synth armor with no misc. mod attached, but if you find one with a misc. mod there is no option for just 'no mod' like there is for all other armor types.
I like to strip my armors down as I collect them and this has been really annoying for me. I may go ahead and add the beta if this is fixed.
Thanks.