Hi @Marina481
We have not opted in to the new software release and have not seen these errors.
As you mention, the problem is when you are in the messages tab. It's possible you are right that since you opted in early to the new release this is related to that? One host I work with using the new software, I have noticed that sometimes the messages in the App are not synced with the messages when viewing on a browser (info has changed in the message on the computer, but not in the App message view). For the time being, try to only access messages in the App and use the computer for everything else if possible.
I have only seen the "parse" error in the past when trying to open up a Host Guidebook that has a large number of entries (file size too large). It's probably best to forward the screen shots to Airbnb and maybe try what @Marie8425 suggests to get around this in the mean time. You can also try a different browser on your computer (use Firefox instead of chrome). However, in the past when I did that, I still got the error on the other browser.
I don't like clearing my cache, as it removes all my bookmarks. You could try logging off Airbnb on all devices (Tablet, phone, computer). Then try logging back into Airbnb on your computer only using your email (not phone number).