Front-end: PHP notice on a post

After activation (no settings were changed or saved) I have opened a post on my site, and added ?amp to get the AMP version. Above a post content I see these notices:

Notice: AMP_Post_Template::verify_and_include was called incorrectly. Path validation for template (...\wp-content\plugins\accelerated-mobile-pages/includes/vendor/amp//templates/bread-crumbs.php) failed. Path cannot traverse and must be located in <code>WP_CONTENT_DIR</code>. Please see Debugging in WordPress for more information. (This message was added in version 0.1.) in ...\wp-includes\functions.php on line 4139
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Notice: Only variables should be passed by reference in ...\wp-content\plugins\accelerated-mobile-pages\templates\design-manager\design-2\elements\bread-crumbs.php on line 71

Notice: Trying to get property of non-object in ...\wp-content\plugins\accelerated-mobile-pages\templates\design-manager\design-2\elements\bread-crumbs.php on line 82

Notice: Trying to get property of non-object in ...\wp-content\plugins\accelerated-mobile-pages\templates\design-manager\design-2\elements\bread-crumbs.php on line 82

Also, note a double-slashes problem: /amp//templates/.

Developers, please, PLEASE use WP_Debug while developing your plugin.

• This topic was modified 6 years, 7 months ago by Slava Abakumov.
• This topic was modified 6 years, 7 months ago by Slava Abakumov. Reason: to reflect a number of notices