I wanted to send an artillery piece from a detachment to the Army HQ, however I couldn't do that because it told me that the MAX of Corps had been already reached in the Reserve. That is all fine, the Reserve amount matched the General's Pursuit value (or HQ value if no General present), however isn't it that support units such as tanks and artilleries do not count to the stacking or Reserve limit?
I had to first put one unit to the fornt lines again then move the Artillery and then move the previously placed front line unit back into the Reserve.