Is the playhead supposed to move during playback? (It doesn't)

The playhead doesn’t move during playback on my Mac.

So I searched this forum and found two other users with the same problem. One of them implied that it wasn’t supposed to move.

However, I also asked Toon Boom about the issue and the supporter said that the playhead stops moving on his system if the project uses too much memory. Which obviously meant that it did move under other and less demanding circumstances.

Mine doesn’t move in inch, however, no matter if the project is small or large, and I’m on an 8 core MacPro w/ 18 GB ram.

So should it move or not?

And how do you navigate if it doesn’t?