Amount property is not working with custom post types!

Hi mate, I have been using your plugin for a long time. So far it worked great.
Now I have 2 custom post types along with 1 default wordpress blog post(posts). I want to display 10 authors in the list who has created most number of total posts (including custom post types)
I used:

[authors_list style="4" columns="1" show_bio="no" amount="10" only_authors="yes" show_count="yes" authors_list post_types="post,photography,streaming" 
order="DESC"  authors_list orderby="all_post_count"  title_element="text" columns_direction="vertical" avatar_size="45" show_bio="no" show_link="no" skip_empty="yes" roles="author" count_text="Points"  ]

Custom post types and total number of posts are working fine.However, whenever I try to put the amount it is showing random authors in the list (Not showing the Authors with maximum no. Of posts).
I tried almost every combinations with these properties. (It is working fine with Blank Amount.)
Thanks in advance. Looking forward to your reply.