Participant Search - Failed to interpret input for search
This appears to be a bug since i can replicate at https://dmaster.demo.civicrm.org/civicrm/contact/search/advanced?reset=1



gives

Sorry, due to an error, we are unable to fulfill your request at the moment. You may want to contact your administrator or service provider with more details about what action you were performing when this occurred.

Failed to interpret input for search

Have mentioned in https://chat.civicrm.org/civicrm/channels/product-maintenance