My daily driver board for the past 3 years has been using Tai Hao caps. The spacebar has a shiny patch where I hit it, but nowhere on the board would I describe as feeling 'sticky.' It's higher friction on the smooth part if I run my finger across it, but that's to be expected, and it does not match the "soft touch/rubberized" description. Same with all of my keyboards, some of which are decades old.
So far it's unclear whether the OP is describing an artifact of a purely mechanical nature (smooth vs textured plastic) or some chemical change.