My understanding is that at least the KAP 200 and 225 will not track a
glideslope (either from an LNAV+V, an LPV, or an ILS) approach when
intercepting from above, which is also my experience.

I also observed that adjusting the altitude with the autopilot up/down
switch will negate the glideslope intercept even from below while in
approach mode. Have you seen this behavior as well?