THIS IS AN ISSUE.

Over sometime (about a month) I have been constructing planes and jets using methods borrowed from those of higher skill. Recently, I have found out, whenever I attach specific connections to that part, and then mirror said part, the CONNECTIONS do not mirror. Especially if it’s a centralized object. This is getting frustrating. I do this a lot with wings, to have them stay inside fuselage under extreme lift. Recently, one my jets, an entry for the Area88 Challenge, encountered slight left roll while inflight. The means is centered, the COL and COT are where they are supposed to be. So what is happening? The connections of the parts on the aircraft; simplistically, something is giving way aka less rigidity than the right side. A friend was able to provide a rough solution to this issue, but I still cannot figure out the part that is causing this issue.