Wrong behaviour after '!signal start-chat'

[mauceri]

I have installed a Synapse server (image matrixdotorg/synapse:latest) along with a mautrix-signal bridge (image dock.mau.dev/mautrix/signal:latest), both containers being launched from the same docker-compose.yaml. Everything seemed to work fine: I invited signalbot to my account, and from the chat room with the bot, I linked the bridge to a device using the command !signal login. The Signal app on the device successfully recognized the QR code, and a success message was displayed in the chat room. After that, I invited another device to chat via the command !signal start-chat , where signalid is the number of the new device. When I send a message from the second device to the first, I am invited to a new room where I can see the message displayed.

Now, the issue I'm facing is the following: "Any message sent from the second device to anyone results in an invitation on Element to join a new chat room where I can see the message!"

If I decline the invitation, it will be sent again when I send further messages. I don't think such behavior is desirable—did I misconfigure something in the config.yaml? What do you think?