Session based AutoForm with custom input type renders multiple times

I’ve created a meteorpad for my issue:
Code version:
Full version:

Have a look at the console in the full version.

I have a collection with an insert and an update form. I’m populating the update form by setting the document _id in a session after clicking one of the id’s in the Files list. This works but for some reason I can’t figure out why my valueIn function from AutoForm.addInputType is firing multiple times when the session changes. Scratching my head on this for some time now. Any ideas?

The meteorpad is a simplified version of what I’m trying to accomplish. I’m storing the template instance but this changes multiples times when my session changes. Need some help on why this doesn’t change just one time…