TOC Quick Search not working on one ItemType - what can be the reason?

Hi community,

I have build a custom ItemType that shall store MAC address numbers. It´s basically a pretty standard straightforward ItemType as we have seen it many many times before.

The keyed_name of the individual items is set on the MAC address itself. So for example an item can have the keyed_name: 12-23-34-45-67

As far as I know, the Innovator 'quick search' in the TOC use the keyed_name to search matching items. This so far worked for all of my custom ItemTypes by default. But it now doesn´t work for this specific ItemType for the MACs.

It doesn´t matter what I enter into the Quick Search field, it never returns any result.

Does anyone know, what can cause this behavior?

1. Does Quick Search require any extra setting beside specifying a "keyed_name"?
2. Does Quick Search dislike my MAC number format with the hypens?
3. Does Quick Search not work, when they are two many items? (the table has hundred of thousands of entries...)
4. Do I need to restart some kind of crawler, similar as seen in Enterprise Search?

I am really confused right now, why only at this ItemType the Quick Search refuses it´s duty. 

Hope anyone can help out!

Best regards