Simulink Diagnostic Viewer does not state source of error

When using Simulink, the Diagnostic Viewer often gives out errors without stating where the error occures. Since my Simulink model is quite large and contains many blocks and many functions it is extremly difficult to debug these kind of errors. I've had multiple different errors with this problem (see example below).

Is this normal? Is there a way to fix this?

This example is particuallary intresting since there is no variable "X" anywhere in my model...:

Thanks for any help!