Bug? AAA fire from emplacements

[Kiwikkiwik]

I notice that the Japanese 25mm AA guns, units 031 and 167 shoot at planes when they are a long way away.
The same guns when emplaced, units 480 and 481 only fire at planes when they are really close.
The different engagement ranges might be about 30 and 5 hexes.
In the Italian OOB
Emplaced units 295, 390, 391, 392, 393, 570, 571, 572, 573, 575, 576, 577, 578, 580
I've checked some of these, they dont seem to fire their AA MGs or their 20mm AA at all.
Maybe one AA MG fired once.
Italian emplaced 37mm AA fires at about 700m Range but not a lot.