Sorry to necro this thread but the "mirror" bug still appears to exist, the only mods I have installed at the moment are ASET, RPM, Vexarp, Mechjeb, Restock/Restock+, JNSQ, and NearFuture. My gut tells me this is a Restock texture issue, but I can't say for sure.
EDIT: Definitely not a Restock or JNSQ issue, I removed them both and still had the same issue.