Ok, it just happened...
Cessna 172 Skyhawk.
Approaching CYVR 26R.
All is well, approach very accurate, descent accurate, reported field in sight and entered glide slope.
Just as I switched from GPS nav to runway 26R ILS nav frequency as indicated by X-Plane map window (111.95), something sends me 45 degrees right, out of glide slope and that's that.
Now, one thing I should mention is that my P2A is on Airac 1801, while my X-Plane 11 runs on the default 1708. This is something I am still trying to figure out how to reconcile. Could the runway's NAV frequency have changed, and my VOR wants to go elsewhere? Doesn't seem like that would be the case because X-Plane is telling me the runway's frequency. Man, I'm confused. I will now try the same flight with P2A disconnected.
If you need log info, I'm not sure how to get that to you. Let me know.
Thank you.