After installing the latest OJS 3.4.0.4 to my 6 months old OJS previous version, Junk characters like ## are appearing before and after all words.
The server did not have latest PHP and the technicians updated this after installation using softaculous installer in the control panel of the website.
What you are seeing are placeholders for the localized strings. For me it did look like this before I ran the upgrade migration. try php tools/upgrade.php check to see if your installation requires it (btw. be sure to have a backup before applying!, this check is save though). Could also be the upgrade failed - then it requires some debugging…