Property updated value not available via key subscript reference

Ignition 8.1.20
Given an array property with a single object element containing a single field:
self.custom.arr[0] = { 'fieldName': 'initial value' } defined in the property tree of any component

Update that object in a script. The new value is available with the get(...) method, but not available through the typical x[key] method.

Example, in a change script:

o = self.custom.arr
o1 = o[0]
system.perspective.print(type(o1).name + ' | ' + o1['fieldName'])
o1['fieldName'] = 'hello world'
system.perspective.print(o1['fieldName'] + ' | ' + o1.get('fieldName', 'default'))


12:47:13.236 [Browser Thread: 54390] INFO Perspective.Designer.Workspace - PropertyTreeScriptWrapper$ObjectWrapper | initial value
12:47:13.236 [Browser Thread: 54390] INFO Perspective.Designer.Workspace - initial value | hello world

Is this expected? Is this new?

Tip: use the </> code formatting button when posting code (rather than the > quotation markdown). It will indent properly (important for Python) and give syntax highlighting. You can use the 🖉 edit link to fix your post.