hi Brigitte,
If you updated both the Moodle and plugin code, then this is a bug. Please file a tracker issue with the steps to reproduce (dont forget to detail: are you on the community finder search page? on the hub search page? what did you select...). You can add a screen capture of the error it help me too
From the error message it seems some comments have an unexpected format. If you don't have thousand of comments on your hub, can you also add them in the issue.
Thanks
Jerome