Conflict with Revisionary

There seems to be a conflict with the Revisionary plugin. When a user with the Revisor role tries to edit a page, this kind of error occurs:

[12-Sep-2017 11:57:21 UTC] PHP Fatal error: Uncaught TypeError: Argument 4 passed to user_switching::filter_user_has_cap() must be an instance of WP_User, none given, called in /wordpress-4.8.1/wp-includes/class-wp-hook.php on line 298 and defined in /wp-content/plugins/user-switching/user-switching.php:816 Stack trace: #0 /wordpress-4.8.1/wp-includes/class-wp-hook.php(298): user_switching->filter_user_has_cap(Array, Array, Array)
#1 /wordpress-4.8.1/wp-includes/plugin.php(203): WP_Hook->apply_filters(Array, Array)
#2 /wp-content/plugins/revisionary/lib/agapetry_wp_core_lib.php(152): apply_filters('user_has_cap', Array, Array, Array)
#3 /wp-content/plugins/revisionary/admin/filters-admin-ui-item_rvy.php(30): agp_user_can(Array, '47', '', Array)
#4 /wp-content/plugins/revisionary/admin/filters-admin-ui-item_rvy.php(13): RevisionaryAdminFiltersItemUI->add_js()
#5 /wp-content/plugins/revisionary/admin/admin_rvy.php(133): RevisionaryAdminFiltersItemUI->RevisionaryAdminFiltersItemUI()
#6 /wordpress-4.8.1/wp-inclu in /wp-content/plugins/user-switching/user-switching.php on line 816

Comments:

• user-switching.php:816 doesn’t seem to have a relevant function call in it
• The user-switching.php filter_user_has_cap() hooked function accepts 3 args
  /revisionary/lib/agapetry_wp_core_lib.php:152 passes 3 args
• The WP filter (https://codex.www.ads-software.com/Plugin_API/Filter_Reference/user_has_cap) seems to accept 3 args
• So, can’t really see where this 4th arg is coming into play and spoiling things!

I imagine the issue, like many conflicts, might fall foul of each plugin developer assuming it’s the other’s problem ?? Also, since User Switching isn’t used regularly, I’ve applied the easy solution of deactivating it, to activate only when needed – so it’s not critical. But I thought I’d notify you, will cross-post to Revisionary.