I have an indicator for earth shield and I have the stack text set to a percent like this:

There seems to be an issue in raids where if I apply earth shield to people the stack text is correct like this:

But If I apply earth shield to anyone in the first group of the raid the stack size is much larger

For future reference, crazy bug:
The game ignores the SetFont() method used inside the icon indicator layout() method if the frame unit is not visible, but only on the second SetFont() call.
To trigger the issue, the fontstring must have a previous font and size assigned and the frame should be a never used precreated unit frame.
Added a ugly fix to delay the font assignment until the frame becomes visible (moved the SetFont() call from Icon_Layout() to Icon_Update() method)
Not sure if the fix will work correctly because i dont know exactly which triggers this game behavior.

2.3.16-beta version may fix this issue.