Linux Joplin App keeps sending reset TCP RST packets to webdav server

As I'm continuing to work on my firewall rules for my https/webdav server, I notice that joplin linux desktop app always sends RST packets to the webdav server. Do we know why? I'm not sure that this is typical...

Upon startup of the Joplin app, the app includes to send five (5) TCP RST packets to the webdav server. Any ideas why Joplin would want to reset the TCP connection? I get no errors upon synchronisation.

I remember fixing a similar issue, might be a regression.

I have tried to replicate this but could not. Maybe it's because I was running apache locally and used plain http rather than https.