Subtask name being removed when marked complete

I have two rules set up in this project. One that names the task/subtasks when the due date is selected, and one that routes to a completed section when a task is marked complete. I can’t figure out why the subtask naming convention is deleting once the subtask is marked complete. Ex.

When left incomplete


When completed:

Hi @Tina_Hasko and welcome to the forum,

If you look at the All activity tab at the bottom of the subtask’s detail pane, that will hopefully give you the answer, or a clue, as to why it’s getting changed. Most likely there is some rule running that is doing it, and that tab should show you which rule it is.