The vertical scroll bar is missing on the Tasks Timeline module when zooming up.
The zoom level where the scroll bar disappears can vary based on the screen used and its resolution
STEPS TO REPRODUCE:
1. Create a project with a large number of tasks so a vertical scroll bar appears
2. On the Modern UX open the project and go to the tasks tab
3. On the Tasks Grid module, increase the zooming of the browser to 150% or 175%
4. The vertical scroll bar is present.
5. Go to the Task Timeline and look for the scroll bar
Expected Results: The scroll bar to be present
Actual results: The scroll bar is missing
This is caused by DE66775
This is fixed in 16.1.1
Key to reproducing this is to make sure the grid size is sufficient to push the Gantt off the screen. Once that occurs the scrollbar is gone.