Why does the remaining time estimate change on the burndown chart for days in the past?

[Rick]

We're using Remaining Time Estimate to track our sprint work. The red and green lines seem to be working as expected. The problem is that the actual remaining time estimate (RTE) is changing for days that have already passed and it is causing the guideline to move. I don't understand why this is happening. My expectation (and I could be wrong) is that the RTE for a day would be locked in once that day has passed. Let me explain what I'm seeing.

• Our sprint started on November 12th with 456 hours of work. At this point the burndown chart was as expected--showing all 456 hours on the 12th with the guideline starting there.
• Yesterday morning we had just under 400 hours of work left. What was unexpected was that the RTE on the 12th was showing as ~400 hours and the guideline was starting there. In reality we had 456 hours on the 12th and now (on the 17th) have ~400 hours.
• Today we have 376 hours left. Again, this shows as being on the 12th which is not accurate and the guideline is starting there as well. 

I thought that whatever the RTE was on the 12th, it would not change once the 12th had passed. If my understanding of this is wrong, how can I have this work like I expect?

[Rick · Accepted solution]

Well, I found out that our filter was dropping all things with a status category of Done. When I removed that things worked as expected.