OK here are the building you had in your screenshots which are factory buildings not airport buildings...... they just ended up on the Japanese side of this test map which was cleared to base terrain as your screenshots show
This is them targeted by, again, 20 batteries of 7.2in Arty
This is the results of the first bombardment and all of these screenshots were taken immediatly after the bombardment. The map position was not changed
then the second stonk
Then targeted for the third go
Then after that
I watched each barrage very carefully. At no time did a building disapear