Regression introduced in R1 2021 SP1. Possibly related to #6597.
Reproducible in the Kendo UI for jQuery Overview demo, the MVC Overview demo, other demos, and in the attached sample project.
Multiple requests are sent to the Update action. One for the edited task and additional one(s) for the parent task(s) depending on the level of the edited task. This happens only on initial edit of that particular task. Subsequent editing results in only 1 request to the Update action.
Every time a task title is edited, only 1 request to the server should be sent.