Key signature change takes extra space

[Richard Shann]

In this example, after a key signature change there seems to be
unnecessary extra space:

\version "2.25.18"
{
         g'1
         a''
         \key c \major g'
         \key f \major a''
}

I would expect the second of the two a's to be spaced away from the
flat of the key signature change at similar distance as the first a is
from the bar line.
Is that a bug? How to adjust?

Richard Shann