No, I normally play with the keyboard :P It was only for some time, because my other hand was occupied with something else :P Just then I was adding new tracks and the trains started to get blocked. And only after some time I discovered that it was because of the semaphores. It's just strange, becau...

OK, now I understand. I simply forgot that copying in factorio doesn't work like that. I was lazy and only used a mouse without a keyboard. Now I will remember that it is better to use ghost to build I need to assign a mouse button to a new function
Thanks for the help.

Yes, I understand that the semaphores do not connect to the tracks in the other direction, but they also do not connect in the middle of the intersection, as I showed in the video. I spent a lot of time wondering why the crossings weren't working, and it turned out that the semaphores didn't connect...

I haven't found a similar topic.
Semaphores do not connect to the tracks every time if we build them using robots using the copy-paste method. This applies to both types of semaphores.
I am attaching a video that shows exactly what I mean.

Clip: https://www.youtube.com/watch?v=_Bqrb0_AGMw