Hey there,
I encountered that the narrow gauge version of token block and absolute block signals can be placed bi-directional in Pak128.Britain-Ex. extended wiki states that there is no such signal.
Due to this and the fact that this is not possible for rail the normal type of these Signals, I expect this to be a bug.
If you could please confirm this I will fix it.
I have not been able to locate any differences in the .dat files, so this may be a code issue. I shall have to look into this when I am able to do so.