[Plugin: Custom Field Template] trouble on edit post page

I say ‘trouble’ because I’m not actually getting an error, I am getting a completely blank/empty page when doing an edit post.
I have not been able to determine the cause of this issue, although it appears to be when there are more than two values entered for a post in a checkbox field.

When I disable the plugin the issue goes away. I don’t have a particularly large form, and there aren’t all that many options in the checkbox fields (the most is 4)

Any help/suggestions would be greatly appreciated.

This is my first attempt at using this plugin, and I’m excited about it because it does exactly what I need, but I’m a bit discouraged at this point.

https://www.ads-software.com/extend/plugins/custom-field-template/