Can confirm the issue, an easy workaround (although one shouldn't be needed) for this issue is:

("testC" cutFadeOut 0) cutText ["This should not be visible on map screen", "PLAIN", 1, false];

or to call BIS_fnc_rscLayer on the rsc layer (which more or less does the same as the code above)

This appears to be a strange issue with where the camera display is actually being created. The camera display is normally created on the RscDisplayMission display, which causes issues when you quit out of it (i.e. no text showing up). If the camera display is created on RscDisplayMPInterrupt the text comes back as it is supposed to. A quick fix to just get rid of the symptoms is to call showChat = true; on the Exit mode of the a3\functions_f\Debug\fn_camera.sqf script. In the mean time players can fix the symptoms by locally executing showChat = true; in the debug console, or if they have CBA by adding

Can confirm, player count displaying properly on dev build 1.65.138842 . It looks like it was fixed by using lnbSize (good solution, for some reason I couldn't get that to work when I tried).

Duplicate of https://feedback.bistudio.com/T120348 ?

This seems to be an unintended side effect of making the player list a child of RscListNBox, instead of the old RscListbox. when calling lbsize on a RscListNBox the actual output is rows * columns. This can most easily be fixed by updating the display script to take the columns into account.