FSEARCH shows and counts the same line twice

:: zscore.btm score
setlocal

:: these floats are in (0,1] from a uniform distribution
set float1=%@right[-1,%@eval[%@random[1,1000000000]/1000000000]]
set float2=%@right[-1,%@eval[%@random[1,1000000000]/1000000000]]

set z=%@eval[(-2 * log(%float1))**.5 * cos(2 * pi * %float2)]
echo %z

comment
alternatively ...
set float1=%@eval[(%@random[-9223372036854775807,9223372036854775807]+9223372036854775808)/18446744073709551615]
set...