Have a look at save http://server.exp.simutrans.com/debug-saves/depot-start.sve (http://server.exp.simutrans.com/pak128.CS-Ex.zip)
There is a depot near Trnava. Open it and release all trains that are hidden there. The singals ahead of depot are distant and choose signals. But only the first train will properly reserve its path. All the rest will pass at danger and eventually some of them will deadlock on the same platform.
Sorry for the delay in dealing with this. I think that I have now fixed this; would you be able to re-test? Thank you for the report.
Seems to be fixed