Why is my burndown non-linear?

[logman]

There is a non-linear line. How can this be explained? Can I trust this burndown?

[Jack Brickey]

Hi @logman , first this isn't a burndown chart it appears to be a Version report.

In this report there are a number of things being charted. The blue line will not be linear I think as it is driven by actual work and will vary as to predict the actual completion date. At least I believe this is the case.

Here is an article that might be helpful - Version-Report