Playback breaks due to "Node with id ... not found"

[billyvg]

This happens on playback (e.g. on sentry.io)... let's try to capture these console.warn messages as errors on Sentry so that we know how widespread they are.

[bruno-garcia]

This came up again as a possible reason why modals show up but don't close. @ryan953 said:

In those modal & missing-border examples I’m seeing lots of Node with id '###' not found. errors and some js/policy/mixed content errors too.
The missing nodes is the problem, we’re probably missing the message that says to close those modals, or to include the borders/color css.

[mydea]

I think we can close this, or is this still an issue cc @billyvg ?