First of all, awesome plugin! Thanks!
I noticed you guys have some kind of support for WPML, also for sitemaps, with on line 1446 in aioseop_sitemap.php:
if ( defined( 'WPML_TM_VERSION' ) ) $defaults['suppress_filters'] = false;
Different languages/domains on the website are still mixed up though. I think this is an old constant. When I changed WPML_TM_VERSION to ICL_SITEPRESS_VERSION it worked.
So please have a look at it and fix it in a next version (I don't like editing directly in core or plugins :p)
EDIT: little correction. I think WPML_TM_VERSION is a constant of the "WPML Translation Management", which is a WPML add-on. Obviously someone with WPML doesn't have to use that add-on, so I think using ICL_SITEPRESS_VERSION will be the correct way.
Thanks in advance for looking into it :)