As told by TrainSim-Matt in this post the red cross underneath the signal shown below is a bug. route: Rhein-Ruhr Osten service: RE 7 Hagen > Wuppertal (16:36) location: Wuppertal Hbf, eastern end of platform 1 in game time: 17:06:19 Playing on PC (Steam) This red cross showed below the signal at the end of my RE 7 service. It had no effects on the gameplay, but I have been told it is a bug. I was capable of reproducing it by spawning in on foot at Wuppertal Hbf at 17.05 and waiting at the signal until the RE 7 service got a green light. I do not know if this shows on other RE 7 services aswell. I know a there is a similar bug on HMA, for which I will make a seperate bug repors when I encounter it.
It's in a way a deliberate "bug"- acc to Matt, the signal system programmers have signals display that by default if instructed to display an aspect they aren't capable of. Sort of a release-build debugging flag.