I just remarked that my flag weight is shown as
510.0000 instead of
510. Has anyone else seen the same problem?
Flag weights above 500 are by design displayed with four digits after the comma. Up to a weight of 500, a "helpful" flag increases the flag weight by 10, but for higher weights, the increase for a helpful flag is less than 10 -- IIRC, it is exactly 1 for a weight of 625 and 0.1 for the maximum flag weight of 750. Because of the somewhat counter-intuitive formula, a helpful flag at a weight of 500 yields "510.0000", but your next helpful flag will let you advance to somewhat below 520, and the digits after the comma will become useful.
This is no bug, it is a normal behaviour. Quoting the meta.stackoverflow.com post "What is flag weight?":
Why is my flag weight not an integer?
Because flag weight above 500 does not increase in a linear fashion, decimal places are shown for precision purposes and to show you how your flag weight is changing.