It appears like certain user input can cause PHP to throw a fatal error on FundraisingFrontend:
[07-Nov-2018 15:30:53 Europe/Berlin] PHP Fatal error: Uncaught TypeError: Argument 1 passed to WMDE\Euro\Euro::__construct() must be of the type integer, float given, called in /usr/share/nginx/www/spenden.wikimedia.de/release-20181101181039/vendor/wmde/euro/src/Euro.php on line 62 and defined in /usr/share/nginx/www/spenden.wikimedia.de/release-20181101181039/vendor/wmde/euro/src/Euro.php:24
Stack trace:
#0 /usr/share/nginx/www/spenden.wikimedia.de/release-20181101181039/vendor/wmde/euro/src/Euro.php(62): WMDE\Euro\Euro->__construct(9.2233720368548E+20)
#1 /usr/share/nginx/www/spenden.wikimedia.de/release-20181101181039/app/Controllers/ValidateFeeController.php(50): WMDE\Euro\Euro::newFromString('111111111111111...')
#2 /usr/share/nginx/www/spenden.wikimedia.de/release-20181101181039/app/Controllers/ValidateFeeController.php(25): WMDE\Fundraising\Frontend\App\Controllers\ValidateFeeController->euroFromRequest(Object(Symfony\Component\HttpFoundation\Request))
#3 /usr/share/nginx/www/spenden.wikimedia.de/release-20181101181039/vendor/symfony/http-kernel/HttpKerne in /usr/share/nginx/www/spenden.wikimedia.de/release-20181101181039/vendor/wmde/euro/src/Euro.php on line 24Taken from php-errors.log on production.
Note: This happened during the cat17 vs 10h16 skin test, it could be that the issue is somewhere in 10h16 but I have not looked into this at all at the time of writing this.