Wrong color order

[ferenczy]

Let's have a very simple configuration:

regexp=^(test1\s)(test2\s)(test3)
colours=red, green, yellow

And the input to be colorized:

test1 test2 test3

I would expect to have the string test1 in red, test2 in green and test3 in yellow color.

But colors are actually shifted one group to the left, so test3 is red, test1 green and test2 yellow:

I have found a workaround: simply add another color at the very first position:

regexp=^(test1\s)(test2\s)(test3)
colours=default, red, green, yellow

Now, it's colorized as I would expect it to be:

Do I understand anything wrong or is it a bug, please?