Maybe those items are free for everyone? IDK since I have the DLCs, so I can't test it myself

@LuizBarros99
The second screenshot shows that they are still premium items and still show adverts on the screen.

Turns out I accidently left this comment as a draft and forgot to publish it almost a year ago. whoops.
This is my current work around that solves the issue. Although it won't be the exact fix for this issue and there is probably a more optimized version, it does show how I've gotten around the issue.

params [["_config",configNull]];

private _dlc = "";
private _addons = configsourceaddonlist _config;
if (count _addons > 0) then
{
	private _mods = configsourcemodlist (configfile >> "cfgpatches" >> (_addons#0));
	if (count _mods > 0) then
        {
		_dlc = (_mods#0);
	};
};
private _configdlc = getText (_config >> "dlc");
if (!(_configdlc isEqualTo "") && {(tolower _dlc) in ["","a3","officialmod"]}) then { _dlc = _configdlc };
_dlc

Basically if the dlc returned is either " ","a3" or "officialmod" (aka. the base game files), then it will check to see if the config has a dlc listing within it. It then replaces the base game dlc string with the correct name from the config.
I've tested it in-game and this fixes the above issues without interfering with the original output.