Some time ago, one of our clients experienced an unusual situation with an enterprise project in Project Online. The client is using the Timesheet feature in Project Online to capture task progress entered on a daily basis by team members. The project contained task splits in the future, and the client could not determine why.
After studying the project in depth, I was able to determine the source of the task splits in the future. Allow me to share the results of my research with you.
Figure 1 shows a sample project that I set up to mimic the behavior the client was seeing. This figure shows the project after one week of updates were applied by the project manager. Notice the following about this project:

Figure 1: Gantt Chart view before updates
Figure 2 shows the project after the project manager approved task updates from the team members for the week of July 16. Notice the following about this project:

Figure 2: Task split in the future on the Build task
If your organization uses the Timesheet feature in either Project Online or Project Server, you should be aware of the behavior documented in this blog post. There is a good possibility that you will see task splits in the future whenever you use tasks with long Durations and team members enter early progress on a task using the Timesheet in Project Web App.
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