field based visibility rules causing major fail

If I create any field based visibility rules on panes in a panel setup and click ok, then check the drop down it says 'target_id equals' for the visibility rule.
Clicking that to edit the rule ALWAYS results in:

An AJAX HTTP error occurred.
HTTP Result Code: 500
Debugging information follows.
Path: /panels/ajax/editor/access-configure-test/panel_context%3Anode_view%3Anode_view_panel_context_3/23/0
StatusText: Internal Server Error
ResponseText: 

Saving the node panel at this point turns the page to an Error:

EntityMalformedException: Missing bundle property on entity of type node. in entity_extract_ids() (line 7539 of /public_html/includes/common.inc).

and due to the first AJAX issue above, the only way to fix it is remove the panel pane completely and add it again, which fixes the page to its former state.