Since you created the package using cmd there is a good chance that you are using some old component package.

Is this happening after instance upgrade ?

To my knowledge the "index" property indicates if this property should be indexed which can be used for fulltext index in which some properties may need to be excluded from getting indexed.

Adding to what Leo has mentioned the following doc can be useful:Using Using Editable Page Templates Page Templates - Editable

By "authoring tag" are you referring to tagging multiple pages with an existing tag under the same node OR creating a new tag and applying to multiple pages under the same node ?

Please read relevant documentation: Security

Do you see the same behavior in the later service packs ?

Ref: The problem appears because the snippet variable is not an object but an array.It seems to be a case of calling a method of some object X to object Y while they don't share the same method/properties i.e. An array object doesn't have a indexOf method 

Usually a deadlock could cause high CPU usage. You can check the following document where you can find info on how to analyze sloe and blocked processes:  Analyze slow and blocked processes

It has happened in the past for other sample site where Adobe no longer updated or enhanced Geometrixx content.