Unable to start Signal Addon due to lack of configuration on 1st attempt

[owldown]

• Installed the Addon
• Clicked Start to start the add on
• "Go to configuration" pops up with "value must be one of ['json-rpc', 'native', 'normal']" and buttons for CANCEL and EDIT CONFIG
• Click EDIT CONFIG
• switched to Configuration tab, which reads "This add-on has no configuration"

If editing the config is required, how do I do that?

Log shows nothing, add-on is not started.

I tried uninstalling and reinstalling, and now there is a configuration tab with radio buttons. I chose json-rpc, and now the add-on starts. Not sure if this is a bug or a fluke, but it didn't work as expected the first time.