Please help understand lines in nextcloud.log

my nextcloud is working fine with version 15.0.7.
Since a few days I observe for inexpliccable line like this in my nextcloud.log.
{„reqId“:“iYLX1CqzA7MffTlt4Axt“,“level“:3,“time“:“2019-05-02T15:06:07+02:00“,“remoteAddr“:“84.166.73.253“,“user“:“nextcloud_root“,“app“:“PHP“,“method“:“GET“,“url“:“/apps/logreader/settings“,“message“:“array_merge(): Argument #2 is not an array at /var/www/nextcloud/lib/private/Files/Type/Detection.php#149“,“userAgent“:“Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0“,“version“:“15.0.7.0“}

{„reqId“:“iYLX1CqzA7MffTlt4Axt“,“level“:3,“time“:“2019-05-02T15:06:07+02:00“,“remoteAddr“:“84.166.73.253“,“user“:“nextcloud_root“,“app“:“PHP“,“method“:“GET“,“url“:“/apps/logreader/settings“,“message“:“array_merge(): Argument #2 is not an array at /var/www/nextcloud/lib/private/Files/Type/Detection.php#104“,“userAgent“:“Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0“,“version“:“15.0.7.0“}

{„reqId“:“iYLX1CqzA7MffTlt4Axt“,“level“:3,“time“:“2019-05-02T15:06:07+02:00“,“remoteAddr“:“84.166.73.253“,“user“:“nextcloud_root“,“app“:“PHP“,“method“:“GET“,“url“:“/apps/logreader/settings“,“message“:“Invalid argument supplied for foreach() at /var/www/nextcloud/lib/private/Files/Type/Detection.php#107“,“userAgent“:“Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0“,“version“:“15.0.7.0“}

I’m at an absolute loss - and delete the nextcloud.log of the previous day.
Please help
BenBenna