Is there a problem with the use of DSS (DirectDraw Surface) files in add-ons

[Atlan]

In the past month I noticed that one add-on after the other stopped displaying icons on macOS. While the game itself is not affected. Talking to other players it is clear that on Windows the add-ons work fine.

I tried to investigate and find out what could be problem. Doing so I noticed that icons are stored in DDS files. DSS (DirectDraw Surface) is a Microsoft prohibitory format format for storing textures and on Microsoft Windows DDS support is build into Direct X.

First I thought that macOS might not be able to load DDS file. But this is not true. The QuestMap add-on has two icon sets. One set that works and one that does not. The sets are defined like this:

--[[

Quest Map
by CaptainBlagbird
https://github.com/CaptainBlagbird

--]]

QuestMap.iconSets = {
    QuestMap = {"QuestMap/icons/pinQuestUncompleted.dds", "QuestMap/icons/pinQuestCompleted.dds"},
    ESO = {"/esoui/art/floatingmarkers/quest_available_icon.dds", "/esoui/art/icons/achievements_indexicon_quests_down.dds"},
}

From what I can see one set is provided by the add-on the other by the ESO itself. The one provided by ESO works fine. I have been looking for the files mentioned but could not find them anywhere. (Side Question: Is there a list of provided DDS file anywhere?)

Question: is there a problem with the use of DSS (DirectDraw Surface) files in add-ons? Could it be that the macOS library loading DDS files is outdated, reduced in functionality or just buggy? Or is it something entirely different I have not thought of?

I attached 4 screenshots using the Quest Map add-on to show the problem. The first two show not marker the last two show the marker correctly.