Just updated from 12.2.1 to 12.5.1. When I put a file to the existing document page by drag'n'drop the following message appears in the log (see msg1 in attached logfile). After clicking Save button and than Save and Reviev there are no errors but attachment becomes missing on the updated page. Sometimes during this operation there is an another error in the log (see msg2 in attached log file) and on the page - Error while evaluating velocity template [previewdiff.vm]. The page contains some hundreds of attachments created within xwiki 12.2.1.