“Avoid Duplicates” option in the post widget results in a 500 error

Hello, thank you for your great plugin. It is very useful and well done. I’ve noticed 2 bugs, that are easy to reproduce:

1. The “avoid duplicates” option is broken. Turning it on, result in a “Server error (500)” when trying to save the page. Same results on several different websites.

2. The “post per page option” disappear from the layout section, when selecting the main query instead of the custom query.

Please let me know if you need more information. Thanks!