UR teach pendant doesn't show what line is running

Hello,

I’m supporting a project that has a UR20 robot, the program is over 3000 lines total. The main program calls sub programs depending on what part type the operator chooses. All the actual moves are in the sub programs. When running the program from teach mode, the blue arrow is supposed to indicate the current running line. Instead it shows only down to the case or if statement and doesn’t show the actual move that is running in the sub program.

Is this a known bug or limitation with UR or is there a way to make this function as expected?

Thanks,
David