Text fields blank

I’ve been using Participants Database for over a year without a problem but recently the text fields are blank when editing a record. They do not display the current values as expected. Whether the record is accessed from a page with [pdb_record] or via the Private ID in the admin’s “List Participants”, the result is the same. Radio-button fields display as expected but Text-line fields are blank, where they should display name, phone etc. The current data does display on a page with [pdb_list search=”true” display_count=”true” sort=”true”]. But as I said, if I edit a record the text-line fields are blank. There have been no changes to the site other than updates. Any ideas?