Since I don't use Chrome, I will leave it to Grace and Heffernan to respond to your question.
This issue seems to have resolved itself and I no longer see it happening.
Sorry i didnt mean to ignore you by not mentioning Edge.
To be honest i dont know exactly how Edge works, if it uses an embedded flash player or not. So thats why i didnt give any info about Edge.
I think this is a memory problem (which is browser unrelated).
If you want to simulate a high memory usage, you can go visit a lot of neighbours (even undiscovered ones). Each time you visit someone the game seems to use a bit more memory. I suspect when you do this, you will see the issue again.
That being said, if it indeed is a memory issue, i dont think the devs can do much about it (inherent to flash), they can make it a bit better by making the game use less memory, but the same issue will keep existing it will just take a bit longer till you notice it.
So please prove me wrong by finding some exact reproduction steps so we can exclude memory problem, because then the dev can fix this