Api stopped returning rich content if blog contains button

Question:
any ideas why Api stopped returning rich content if blog contains wix button.

Product:
Wix api for getting blog post.

What have you already tried:
It was always working but now it return nothing. Removing the button and it will return the rich content after publish.

Additional information:
calling http://www.wixapis.com/blog/v3/posts to get all post and set the fieldsets with [‘RICH_CONTENT’, ‘URL’]

maybe this is the bug from wix side?

Thanks

Can you share code and steps that reproduce this issue?