Our company polices states that crew can form a bubble and act like they're in a bubble if they wish.
Your company policy appears to be obviously wrong because
it's not the same crew:
We are with different crew on most layovers. For example I could go to New York tomorrow with one set of crew and spend the layover with that same crew and fly back with the same crew. And then 2 days later I could go to Los Angeles with all different crew expect one or 2 people who I might have been working with on the last layover. [..]
In this context, "bubble" does not mean "some people who happen to be together at the time".
[..] During this layover we (the team of crew that are working together on the flight after the layover) usually go out for breakfast and dinner together and often sit around the same table closer than 2 meters like we would in normal times. A few staff in restaurants have commented saying we shouldn't all be around the table and then when we tell them we work together and can't social distance in work then they still say that we are behaving inappropriately and should social distance and we have had a few other quite rude comments.
Do you think we should be social distancing during the layover's?
Yes. Partly because you are
not a bubble (company policy does not override reality) and partly as an example in public. Groups of people ignoring social distancing rules in restaurants set a bad example and make life harder for the restaurant staff. Say, for example, I'd gone to the same restaurant with several people I knew but was not in a bubble with. We're socially distancing. Your group (which is also some people who know each other and are not in a bubble) is not socially distancing. Someone in my group asks the restaurant staff why we have to socially distance and you don't. It's now a problem for the restaurant staff. A problem you've made for them.
I think your actions are more rude than a few restaurant staff saying that you're behaving inappropriately.
On the one hand, your job requires you to break social distancing rules intended to slow the spread of the pandemic. Your employer is pretending that's not happening, probably as a legal arse-covering exercise. But it is happening. So it could be argued that it doesn't matter on the basis that if the crew was going to cross-infect each other due to lack of social distancing then it would happen during a flight so it doesn't make it any worse for them to not distance at any other time too. But more opportunity for infection is more opportunity for infection. Several days during a layover is longer than a flight. There's also the social aspect, as I mentioned above.