We have had very rare reports of this happening to a few users over the years, but this is not something we’ve been able to reproduce nor something we’ve experienced on Event Smart where we have several thousand sites hosting events and accepting registrations. So, whatever is happening is likely an extremely rare situation with several niche factors. However, our team did look into the related systems (messages and crons) last week. So far we don’t have any more information to offer, but we’ll let you know if/when we have something. If you can give us any more context about your server configuration, theme, active plugins, PHP, MySQL, Server OS and version, that might be helpful.