All subtasks show 00:00 time tracked. If I open the subtask, then the list view will sometimes update to show the correct tracked time for this subtask. Sometimes its just visible for a moment and then displays 00:00 again.
FYI: I already mentioned this bug in an email about another visual bug with the time tracking feature (https://clickup.canny.io/bugs/p/time-tracked-wont-show-in-task-display)