I'm running into a problem with event registration pages. Since upgrading to CiviCRM 5.14 & 5.15 whenever a user clicks continue on an event registration page it appears to refresh, not advancing to the confirmation page. We are placing a shortcode on these pages to display the registration form. It doesn't seem to matter if I set hijack to 1 or 0.
Initial registration slug:
After clicking continue, but a blank registration form appears:
We are running Wordpress 5.2.2 and CiviCRM 5.15 currently. I have not adopted the clean URLs introduced in v5.13, but I suspect something in this update is causing the issue. If I temporarily revert back to CiviCRM 5.12.4 (with the same 5.15 database) the event pages advance as expected.
At the same time the live links CiviCRM provides to check out an event registration page aren't loading in v5.15, but they are in v5.12.4. In v5.15 all I see is the default "Do not delete this page. Page content is generated by CiviCRM".
Doing the standard cache clearing and updating resource URLs doesn't seem to help. Any ideas on what I could try? If I permanently revert back to 5.12.4 and keep the database at 5.15 would there be any issues?
UPDATE: I tried completing a test registration with v5.12.4 and ran into a database error once I confirmed the registration. We decided to revert the entire site to a backup before the upgrade to 5.14. We'll want to upgrade later on so I'm still interested in ideas for getting this resolved.