Indirect tag value

Ignition 8.1.7

I have a property bound to an indirect tag.

If custom.TagPath is null, the bound value shows null correctly.
If custom.TagPath is an empty string, the bound value becomes:
The component shows:

What’s the data type of the tag you are binding to? And I presume that the issue is that the bound component is showing 14? What should it be showing?

Did this behave differently in earlier versions?