AP says: AP: got MISSION_ITEM; GCS should send MISSION_ITEM_INT

[AndKe]

reproduced in SITL, when uploading mission to ArduPlane, console says
"AP: got MISSION_ITEM; GCS should send MISSION_ITEM_INT"

[AndKe]

Also: AP2 is unable to request a mission plan from Ardupilot (also reproducible in SITL)
If a mission plan is requested by another GCS (like MAVProxy, AP2 will actually populate the plan just fine.

To reproduce:
Start SITL (make or load mission)
Connect AP2
observe that there is no mission
In AP2 - observe that "read" and "refresh" buttons do nothing.
in SITL terminal , enter "wp list" (requesting mission)

• observe that mission is properly populated.

I suspect it may be due to the use of https://mavlink.io/en/messages/common.html#MISSION_REQUEST
(note the red text)

@Arne-W - are you familiar with this/what do you think? (I see no obvious way to see MAVLINK messages used)