There haven't been any reported issues with Sitefintiy runnign under AWS when using it as Load Balancer service. We offer load balancing support out of the box through our Load Balancing module. You can read more about it on this section
from our documentation.
The only condition that you'll need to meet is that the nodes can communicate between each other (i.e. each node is accessible from the other node) and you know the addresses of each node, so you can configure them in Sitefinity's Load balancing module.
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