I also work for a large SW company with our own legal department and their statement was exactly the same - using Elasticsearch is not an option anymore and we are migrating to Opendistro. The Intellectual property advisor that I was in contact about the changes said that the blog, comments of Elastic employees swearing that our use case is permitted (we use ES on customers sites as a service but only internally without letting anyone outside of our company connect) and FAQ section is simply meaningless. The only text which matters is the official license which leaves so much space for uncertainty and for a few billions company a doubt in this case simply means no doubt - Elasticsearch should be replaced by its Apache 2.0 alternative if available.