I also have problems when using the Most Liked Widget for certain selected categories.
All is working fine when no specific categories are selected in the widget settings. However, the widget only displays one post when a specific category is selected, although there are at least 3 posts to display in this category.
I have checked and re-checked and re-re-checked to try to understand if I was doing a mistake somewhere… but no, it looks like there is a bug when selecting one (or more) category in the widget settings.
I am using last versions of WordPress, Buddypress and WTI Pro.
PS: sorry, my site is not yet public, I can’t give a link.