[BUG] Crashes when trying to edit past events

Event Organizer has stopped working for us while trying to edit past events. We are given a bunch of these errors while trying to access and edit a past event through the backend.
Is there a problem with our date format? We use international format ISO 8601; ie YYYY-mm-dd hh:mm

Bugreport from WordPress email. First line in swedish however, but basically says “an error of the type E_ERROR occured on row 31 in the following file:”
Ett fel av typen E_ERROR uppstod p? rad 31 i f?ljande fil: *********/public_html/wp-content/plugins/event-organiser/includes/event-organiser-utility-functions.php. Felorsak: Uncaught Exception: Error in formating DateTime object. Expected DateTime, but instead given string in *********/public_html/wp-content/plugins/event-organiser/includes/event-organiser-utility-functions.php:31
Stack trace:
#0 [internal function]: eo_format_datetime(‘2014-09-11 20:0…’)
#1 /*********/public_html/wp-content/plugins/event-organiser-pro/includes/register.php(396): array_map(‘eo_format_datet…’, Array)
#2 *********/public_html/wp-includes/class-wp-hook.php(287): eventorganiser_pro_admin_enqueue_scripts(‘post.php’)
#3 *********/public_html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#4 *********/public_html/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#5 *********/public_html/wp-admin/admin-header.php(104): do_action(‘admin_enqueue_s…’, ‘post.php’)

Using WordPress Version 5.4.2, Event Organizer Version 3.10.0, Event Organizer Posterboard Version 3.0.1
And Event Organizer Pro that stopped updating after Version 1.10.4, with no access to newer updates. As well as Event Organizer Front End submission Version 1.3.2

The page I need help with: [log in to see the link]