Good day.
We find that if you have predecessors, at the time of entering them, the dates update. But when you go back to the date that was adjusted based on the predecessor relationship, you can change that date to anything and the predecessor will just stay there, invalid. In the attached screenshot, we have task line 6 and task line 10. I said that task 10 should start after completion of task line 6, using 6FS as predecessor. But then I went back to task 10 and changed the date to something in the past, and it accepted it, but still leaving the condition that task 10 should start after completion of task 6. When you do this in MicroSoft Projects, it flags an error and the user must resolve it. You can choose to delete the relationship, or respect the relationship, in which case it pulls the start date of task 10 back to after finish of task 6.
Attachment:
Syncfusion_Gantt_Control_86e09c58.png