yuri878,
We added to last plugin release option that allows to option allows to enqueue scripts and styles only for the pages with contact form. This should prevent conflict with other reCaptcha, except situation when you have 2 reCaptcha on one page.
Also, based on your site link, you used simple reCaptcha integration that allows to use only one reCaptcha on the page. Our plugin use more complex integration that allows to use several reCaptcha on one page, but it is working only for our plugin.
Based on this it is conflict of these different solutions and unfortunately we can’t fix it globally.
More information about the reCaptcha ussage you can find here.
Please let us know if this will help you.
With kind regards,
WebCodin Team