Adult Verification Plugin blocking Google Bot

Ah, crap guys. Just noticed that my Age Verification Plugin for Wordpress also blocked the Google Bot even so the settings were to let it through. After deactivating and activating the setting the Bot can now see my site normal (Search Console). And I wondered why my site dropped so hard...

Now to my question: Could this plugin also be seen as an intestinal Pop-Up? I need such a plugin and I'm now unsure whether to use it further. Does anyone know of a different one that is good? I've searched a lot. Is a splash page a better option?

Btw. Plugin is http://agsoft.com.au/plugins/adults-only-age-verification-system-for-wordpress/