Logic shows mono-to-stereo when it should not

Re-posting because the situation is different from my earlier question, in case anyone has any insights:

We define the valid I/O channel configs as {1,1},{2,2} in our .jucer file. But for some reason, in Logic, it shows a mono-to-stereo version as being available. Clicking on that will cause an error window to appear, telling the user to check with the manufacturer to resolve the issue. Which means we would get calls on this. How can this be? The scan in Logic says (in TWO places) that the only legal arrangements are 1-1 and 2-2, not 1-2.

Strangely, I never saw this until very recently, but our QA has said it’s been like this for a while. And now another dev who was unable to see it happen also reports seeing it happen.

Is this purely a Logic bug? Or is there perhaps something besides setting that field in the .jucer that might fix this?

I tried using code instead of the .jucer field to fix it, but that did not work, either. (IN fact, that was how it was written originally, and I switched to using the .jucer field to try to fix it.)

My boss is not satisfied with saying it’s a Logic bug, because, in his words, “it doesn’t happen to any other plugins”. Sigh.

I had the opposite problem when I tried to add a {1,2} config to a plugin only supporting {1,1} and {2,2}. It worked everywhere but in Logic. Even rescanning the plugin inside Logic wouldn’t make it update.
What helped in the end was increasing the version number of the plugin as only this seems to trigger a full rescan that includes channel configs in logic. This of course would only apply to your case if your plugin previously had a {1,2} config.

Looks like using their Plug-In Manager and clicking on Full Audio Unit Reset fixed the issue, for me, at least. Found that in this thread:

Worked for our QA folks, too!