Confirm, problem still exists... push...

I can confirm, that

respawnTemplates[] = {"MenuPosition"};

affects your playable unit's spawn location/start position and will not have them start the mission from where you've actually placed them in the editor.

This is some kind of a major issue for mission building.

Yes, that's right, addon by Mondkalb:
https://forums.bistudio.com/topic/143212-mbg-killhouses-arma3/

Any news on this topic?

Error: EntityAI SubSkeleton index was not initialized properly (repeated 1826x in the last 60sec)
name: MBG_Warehouse_InEditor, shape: mbg\mbg_killhouses_a3\m\mbg_warehouse.p3d, index: -1, matrices: 18

Is there something the addOn-builders can change in their addons to solve the issue?