Critical path stop working with milestone

I’m adding critical path to gantt chart.
Generally it works fine, but when I add milestone to critical path it stops working.
You can find more details on attached screens:

Hello Wolland,
The milestones have a 0-day duration. So, it’s successor should start the same day the milestone starts to make the milestone critical. And for its successor to be critical, it should end the same day the milestone starts.
If the duration_unit is "day" (default), Gantt will round the duration between 2 tasks. If it is less than 12 hours, Gantt will round it to a 0-day duration, making the predecessor critical. If it is more than 12 hours, the duration will be 1 day and the predecessor won’t be critical.
Here is an example: