Formula Category Gone Haywire

[Darius1968]

So, a folder in my DB contains roughly 2,700 files.  I setup a formula category:  @RFolderRegExp[Nelson].  So far, so good. 
This folder has roughly 350 files with an entry in the attribute:  {File.AT.File Info.Caption}.  Therefore, I go ahead and setup - as a child category to this formula category - a data-driven category based on this attribute, allowing for the display of the so called Other category.  Also, I restrict this data-driven category to files that are in its parent formula category. 

So, it seemed that all was well.  That is, until I changed the formula category to reference a different folder.  Then I start getting erratic behavior - the data-driven category no longer reflecting what its parent formula category has (even after a refresh). 

So, what's wrong here? 

[JohnZeman]

Perhaps it's because your data-driven category is a child of your formula category?

Almost all of my data-driven categories use a formula category to restrict the files processed to what I want but I always keep my formula categories in a totally different branch of the category tree from the data-driven category and I've never had the problem you're experiencing.

For example my

@All|Chronology

data-driven category uses my

@All|Workflow|LISTS|Years

formula category.

[Mario]

Do never nest data-driven categories into other categories.
Especially not when the data-driven category references it's parent in some way.
This is a recipe for disaster (recursive calls, infinite loops) IMatch will break and the result is then undefined.

If you filter data-driven categories by another category, make sure that both categories are separate and have no child/parent relation.