Need advice: Dark shadows developed in screens of 4 different devices within six weeks. May this be an electrical issue?

[static zap]

These modern screens do not have a thick sheet of glass .
(we added acrylic sheet in a workshop situation Tools , springs ..Solder )
Technically we called it Bruising.
Any Wii gaming equipment ! another mechanical favorite.
..childeren , pets and a route to the kitchen spring to mind.

 

[static zap]

Did have another thought , if its multiple devices ---and damp like patches.
a) Low heating + condensation issues.
b) Killing with kindness ... Incorrect cleaning substances / pressure !
(I will admit to Meths myself )
...Do you have a cleaner to blame . (best leave that alone if partner)
.