Definition not working on a different project

I’ve made a definition to change material tag type accordingly to the category of the element it’s pointing to. The issue is that the definition worked on the project I used to develop it but doesn’t work on a similar project, with the same material tag family. The two projects are very similar because they belong to the same complex, so I’ve used the same families to build them. It seems that the problem starts when the definition test the tag’s host category, all I get is a null, or a empty list sometimes. The only differences between the files i can think of is that one was used to develop the definition and the fact i was working at home with the test file and the second one came from the office. The Revit is 2016 and Dynamo is 0.90 in both home and office machines.

Does anybody have a clue why this is happening?

I use windows 7 at home and windows 8 at the office, can this make a difference to the definition?

Sorry the poor english and thanks in advance for your help.

Gustavo

Found the issue: the file where the definition doesn’t work have a linked file ando some material tags points to elements in those files. This generates null results and prevents the host category node from returning a list. Does somebody knows how to filter out tags pointing to linked elements? Or how to identify the category of the host element in the linked file?

Gustavo