Miniupnpd log spamming

I am using miniupnpd for enabling Syncthing, PS5 and Home Assistant statistics. It is rather annoying that miniupnpd pollutes the system log. It is full of messages like

 daemon.warn miniupnpd[20046]: HTTP Connection from closed unexpectedly

Probably the problem is in Syncthing that does not close events right. However, I have no power over Syncthing development. Therefore I wish to mute these messages so that real errors and problems would be more visible. Is there a way to do that?

I am still searching for a solution to this problem. My system log is still about 90% full of these miniupnpd messages. Any suggestions?