Yes. I reached out to support about this and got this answer:
"I wanted to follow up with you on this case. I've been checking the documentation on this, and I was able to confirm that this is expected behavior for the Planner. When viewing the ACT column, it will display the total time entered by the user for tasks that they are assigned to. Since this user logged time on a task that was not theirs, it was excluded."
I asked if there was a way to change a setting to show all hours logged and they said no.