Crash after first execution of retrieving mails or infinite loop

[HighIander]

The plugin connects correctly to my imap, pulls the messages, puts them in the correct thread but then often crashes:

{"level":"info","ts":1613511169.067622,"caller":"bleveengine/bleve.go:267","msg":"UpdateConf Bleve"} {"level":"error","ts":1613511337.1845307,"caller":"plugin/health_check.go:59","msg":"Health check failed for plugin","id":"com.mattermost.mailermost-plugin","error":"Plugin RPC connection is not responding"} {"level":"warn","ts":1613511337.1847084,"caller":"plugin/hclog_adapter.go:69","msg":"error closing client during Kill","plugin_id":"com.mattermost.mailermost-plugin","wrapped_extras":"errconnection is shut down"} {"level":"warn","ts":1613511337.184723,"caller":"plugin/hclog_adapter.go:71","msg":"plugin failed to exit gracefully","plugin_id":"com.mattermost.mailermost-plugin"}

Once I restart, it pulls the same messages from imap again, creating duplicates, and then crashes again.

If it doesn't crash, it still pulls the same messages over and over again. On the server, the deleted flag is set, but the plugin never checks if the flag is set before adding it to mattermost. I think the expected behaviour would be that the mesages actually get deleted. I believe that this only happens once the client is actively closed - which seems to never happen. after the messages are processed.