I dug around some and this appears to be caused by an inconsistency between the mission load out and the static load outs for the UH-1H.
The payload file is missing the door gunners.
DCS World\MissionEditor\data\scripts\UnitPayloads\UH-1H.lua
You can fix it by copying the file to your user profile directory:
\Saved Games\DCS\MissionEditor\UnitPayloads
And change the content to the below. Note you can also create a second load out if you want to be able to select a load out without door gunners.
local unitPayloads = {
["name"] = "UH-1H",
["payloads"] = {
[1] = {
["name"] = "M134 Minigun*2, XM158*2",
["pylons"] = {
[1] = {
["CLSID"] = "M134_L",
["num"] = 1,
},
[2] = {
["CLSID"] = "XM158_MK5",
["num"] = 2,
},
[3] = {
["CLSID"] = "M134_SIDE_L",
["num"] = 3,
},
[4] = {
["CLSID"] = "M134_SIDE_R",
["num"] = 4,
},
[5] = {
["CLSID"] = "XM158_MK5",
["num"] = 5,
},
[6] = {
["CLSID"] = "M134_R",
["num"] = 6,
},
},
["tasks"] = {
[1] = 32,
[2] = 31,
[3] = 35,
[4] = 16,
},
},
},
["unitType"] = "UH-1H",
}
return unitPayloads
There is a second inconsistency that I still haven't figured out yet. The default loadout has 19 missiles per pod. The reload has 7 because that is the number specified in db_weapons_data.lua. I'm still looking for where the 19 is defined.