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

Ref: We are getting this error in the console whenever we try out of the box text componentCan you be more specific:1. What are you doing when you get the error ? Steps that leads to the error2. What version of the product ?

Can you clarify if there has been any customization/overlay in DAM console ?Which version of AEM you are running ?

The following doc can help you with that:Customizing the Consoles

I am assuming you are using granite/ui/components/foundation/form/multifield rather than Coral multifield i.e. granite/ui/components/coral/foundation/form/multifield. Please check this sample to ensure you have similar structure and implementation:Creating an AEM HTML Template Language 6.3 component...

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

there are variety if reasons for this situation. It might be caused due to long running JCR sessions along with online compaction [1]. It can be caused by some older issues in Oak [2], ... etc. So the logs should shed some lights on the probable cause(s).[1] Fix Inconsistencies by restarting AEM whe...

It has happened in the past for other sample site where Adobe no longer updated or enhanced Geometrixx content. 

Are you saying when the index is in use "the same" query returns results ?