Thanks for this amazing plugin. It is extremely helpful for our network.
I've noticed one possible bug related to custom post type permalinks. You've added filters to adjust any tags blog permalinks to the correct site in the network. However, the filter is only applied for posts & pages (around line 590 & 591):
add_filter( 'post_link', 'sitewide_tags_post_link', 10, 2 ); add_filter( 'page_link', 'sitewide_tags_post_link', 10, 2 );
To apply the permalink filtering for any custom post types that are also syndicated to the tags blog, I had to add the
post_type_link filter as well:
add_filter( 'post_type_link', 'sitewide_tags_post_link', 10, 2 );
Just wanted to pass that along for others who might run into the same issue.