Steve- make sure that you are not inadvertently reverting the Pivot View to an earlier state. If you can reproduce, file an error message and send/post a screenshot...also make sure the data type of the columns being changed is not also changing...not all data types can be used as axes in the version 2.5 Pivot View. For example, if you append a lot of new values to what was previously a Category, it may acquire too many unique values and become Text, which cannot currently be used as a axis of a Pivot Table.

Hi, I am not reverting the pivots or changing the types of any columns, in some cases I am reducing the amount of values. The pivot tables aren't behaving like a text field but are just disappearing completely to be replaced with a completely blank space or a different view altogether. Unfortunately I can't post a screenshot due to my companies security policies

Steven- let's escalate this to the support process..please reproduce the problem, then file a bug report using Help > Error reporting so that we can capture version information and your machine state. Then scramble the contents of the file using the Data > Scramble option and verify that the problem persists with the data scrambled and non-pivot columns deleted.Then e-mail us a message at the the private support page:
http://www.visokio.com/private-support

Apologies for the delay in responding to this. I will go through the steps today and send you the results.

Thanks,
Steven