Issues with Joomla 3.8.6 and Jevents 3.4.46

Hello,

One of my sites is on Joomla 3.8.6 and using JEvents 3.4.46 and it is not allowing us to create an event, you can see this screenshot: https://drive.google.com/a/directive.com/uc?id=1XkKO0F9IeeqpQhoJTQ7eLbkk2dBSY3H0 The website should redirect to the add events page when we login to the frotend and press the '+' icon. I have other sites that are working, however, they are either on a previous version of joomla (like 3.8.5) or previous version of JEvents (3.4.43) Have you heard of this issue before? When I enable 'error reporting' it says there is an issue with Joomla Core Library. https://drive.google.com/a/directive.com/uc?id=1S9P9yX38DIsF9ZxSTeqTwkh2EmlrV2XF

I am curious if you can help? Or perhaps we need to test using the JEvents 3.4.43 version of JEvents but I can't find it anywhere.

Thanks!