After taking a quick scan of the Watu (not pro) plugin, I noticed that the plugin is calling
the_content filter hook in a couple of different places. I imagine that's where the "conflict" is. The problem with this is that the plugin is calling a WordPress hook that has very specific "definition" (for lack of a more appropriate word) in WordPress. Basically, plugins like Members and others expect this hook to be executed within The Loop with all the post-related functions available to us.
My guess is that Watu has this hook so that it can execute filters that normally are on
the_content hook for some custom data it's pulled from the database (outside of The Loop and without any post-related functions returning the correct data). Instead, Watu should be using a custom hook here and applying those filters to its custom hook. A simple example of this is something like the following:
add_filter( 'watu_custom_hook', 'wptexturize' );
add_filter( 'watu_custom_hook', 'convert_smilies' );
add_filter( 'watu_custom_hook', 'convert_chars' );
add_filter( 'watu_custom_hook', 'wpautop' );
add_filter( 'watu_custom_hook', 'shortcode_unautop' );
add_filter( 'watu_custom_hook', 'do_shortcode' );
I'm assuming the same issue is with the pro version of the plugin. I'll be more than happy to take a look at it if you email me the code.