Hey @Ian,
Sorry to hear about this! I’m curious about several specific pointed questions – if possible, please address of these points specifically in the order they appear:
1. Can you share a URL to where we can see this issue happening in person?
2. Can you share your “System Information” with us here? This article shows how → https://theeventscalendar.com/knowledgebase/sharing-sys-info/
3. Can you specify what your site’s permalinks settings are if you just literally go to “Settings → Permalinks” in your wp-admin dashboard? What is the setting here? Is it /%postname%/, for example?
4. Does anything improve with this issue if you follow the steps outlined in this article? → https://theeventscalendar.com/knowledgebase/fixing-http-404-errors/
5. If the answer to #4 is “no”, and if possible, please temporarily activate a default theme on your site like Twenty Sixteen. In this theme, does the exact same behavior happen?
Your answers to these 5 questions will provide a ton of helpful information regarding the nature of these issues and help us pinpoint the problem – thank you in advance for addressing them all!
Sincerely,
George