Notice: Trying to get property of non-object in template_preprocess_views_view_fields()

Getting PHP notices in my logs:

Notice: Trying to get property of non-object in template_preprocess_views_view_fields() (line 224 of .../sites/all/modules/views/theme/theme.inc).

Looks like the same issue as reported in https://www.drupal.org/node/1459338, but I don't have Views XML Backend.

This appears to have started with a view that's using an LDAP query. The view works as expected, but the notices are drowning the log file.