Report ID: 1565118282
My word document says that I have updated zotero citations since last time and would I like to make changes. If I click yes to make changes, it goes one-by-one and deletes the first letter of every citation.
Make a backup of your document, then follow debugging broken documents instructions, specifically step 8, isolate the problematic citations/paragraphs and send it to support@zotero.org with a link to this thread.