The bug is basically the following:
Suppose I am trying to edit the BackgroundTransparency (a (possibly) non-integer number value) of a Frame in Studio, and I want to set it to 9/10. Then I have to fill in “0,90” with a comma. However, in the Properties window this will be shown as “0.9” with a full stop afterwards. When I try to append a number to it without changing it to a comma, say “0.95”, it will change into “95” instead of what you would expect it to be.
I think the difference between the dot and the comma has to do with how your operating system is set up to handle input scanning of non-integer numbers, and there is somehow a confusion in Studio between these two methods for that reason, but I’m just guessing there.