that's not a proof in any way as long as it's not reproducible. ;)

Seems 197 persons could actually reproduce the expected result. You're saying it's wrong. Maybe you're right. But you don't give us the input you used, so nobody can check that what you're saying is true.

pro tip: https://github.com/codewars/codewars.com/wiki/Troubleshooting-your-solution (I bet you'll find in there the mistake you did)

;)

I would agree with your decision, but I see a correct output in my IDE (when kata doesn't see it) + I've written my own kata's test where I reproduced this case. And I see the corrected output. The issue is only a final test...

Please which input? Before posting an issue look at the top of the page to see how many people passed the kata (197 with Golang). If this number is high enough chances are that there is a problem in your code.
Not a kata issue but a problem in your code. You should read the description again. Sorry.

The Goland sample test is incorrect for parameters then I should show results between both 10,000 and 9,950.
from description:
(Note: m, n, f, b, c are positive integers, where 0 <= m <= n or m >= n >= 0. m and n are inclusive.)

result from wrong test looks like:
Log
Expected
<[][3]string | len:0, cap:0>: nil
to equal
<[][3]string | len:1, cap:1>: [
["M: 9991", "B: 1427", "C: 1110"],
]