Hi Pieter - I'm not sure without looking into to it further, but I think it could be due to the fact that the gate is shown as "Locked".
I've found this issue where auto plot does not want to go through these gates in "on foot" mode, even while they are tagged for on foot-access in OSM:
Example:
https://www.openstreetmap.org/node/17056090
Since recently it has this problem for all of the gates around this forest (the gates were there before but auto-plot worked without issue then), but I'm pretty sure it is labelled correctly in OSM?