I was working on a custom mission as Independents when I noticed the issue. Radio Support seems to execute the call in correctly but does not provide radio / verbal feedback for successful / denied call in, unless on Blufor.

Test

Map: Cam Lao Nam
Mods: None
Scripts: None

Fresh scenario, placed Independent RTO unit and Radio Support module. Character asks for support (Tested initially with High Explosive -> Commando Vault -> normal payload). No further feedback. Appears to do the same on other call ins. I group the unit to a Blufor followed by Opfor unit to test those sides without changing the spawned unit. Independent and Opfor successfully get ordinance called in however there is no radio dialogue / feedback beyond the initial sentence. Blufor functions as expected / correctly.