Ever since versions 60.0+ this has not worked correctly;

-Pages sometimes need a reload to activate the zoom level.
-When updating to 60.0+ versions it wipes all per site settings. (FF Version 51.0.1)
-Remove that time bomb you have built-in, so if we like a version and a version of FF we can stay at these levels w/o being forced.
-Where is version 56.1 this was the last known properly working version. Why was it removed?
-I'm going to revers engineer to remove the time bomb