Version 1.5 (108.10)
OS X 10.10.3, stock Apache/2.4.10, PHP 5.6.9 (brew) with Xdebug v2.3.2 (brew).

See screenshot: http://cl.ly/image/3G0L0k1J441A
I don't know how to reproduce this yet.

I suspect this happens for some non-local variables in a local context. When 'property_get' is issued, it doesn't specify a context, which defaults to 0, so getting the properties of any variable from context 1 (superglobals) or 2 (constants) fails with the response:

<error code="300"><message>can not get property</message></error>

Top-level properties (such as constants) are retrieved and set by 'context_get', so they're unaffected by this. Also, any existing sub-properties should be untouched, so you may see some values present.