My browser / operating system: MacOS Macintosh X 10.16.0, Chrome 81.0.4044.138, No Flash version detected

I have a code like this

repeat until <(var1) = (0)>
...
if <(var2) = (0)> then
set [var1 v] to [0]
end
end

Simple, but when I run this loop, var2 is set to zero, then I see var1 set to zero as well.
But the loop doesn't end.
I check it by clicking the boolean block to make sure it is correct.
Yes, var1 does equal 0.
What do I do?