Only 2 digits are visible in the size box that holds values between 1.0 and 0. Meaning most values will contain 3 digits. This is different from UE4 where more digits are visible.
At minimum 3 digits would be visible.
Only 2 digits are visible making it hard to determine the value.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-140078 in the post.