Yep, Approach mode is activated. When crossing the IAF the GNS430/530 should transition to LPV, which it does for me every time. I will activate the Approach mode after the final vector to intercept the Final Approach Course. Only rarely does the GS display on the HSI, even though the Approach mode has been activated and confirmed on the Auotpilot annunciator. There is definitely a bug of some sort which may be specific to my x-plane 11 installation but I am not sure how to trouble shoot it.