It's a real headache but should be fully reversible. @shmoogy hit the nail on the head: we'll run through our events in that timeframe, inspect the raw bounce reason to check it relates to the Gmail outage, then undo the actions that the bounce caused.
The reason why this is so nasty is not because Gmail went down, but because they returned a 5XX permanent failure and not a 4XX temporary failure for these bounces. Literally every email provider will respond to a permanent bounce by suppressing all further emails to that email address (it's permanent, after all!), so the fallout from this will be huge.
The reason why this is so nasty is not because Gmail went down, but because they returned a 5XX permanent failure and not a 4XX temporary failure for these bounces. Literally every email provider will respond to a permanent bounce by suppressing all further emails to that email address (it's permanent, after all!), so the fallout from this will be huge.