Concurrent modification exception in BaseSite

It seems like the error is not present in the 11.3RC01 qa server. As there is no clear way to prove it, the absence of the error feels like a good proof to verify as resolved in 11.3

I thought that when we put a site into the cache we copied it and when we got it out of the cache we copied it, so that it shouldn't ever be the case that 2 threads are modifying the same site object.

There could be instances where a tool puts a site object in a session and then a users makes 2 concurrent request, but we can't help tools that are doing that too much.

However I don't think any 2 calls to the kernel getSite() service should return the same site object.

The error is raising in home page with multiple synoptic tools loading at the same time, so I guess is a concurrent safe issue.

Are we saying that Site objects should be considered concurrent safe?

The error is pretty similar to this so I guess we could solve it with a similar fix.