Wiwi,
Based on your WinMTR it looks like you are getting the correct latency for the route you’re taking. It is possible that something changed in the route, but I’m not aware of any changes that have been made on our side that would affect this.
Your internet provider is primarily responsible for routing you to where your connection needs to go. So it is possible that something changed on their end or with one of the peering networks that is being used.
Morogoth - I don’t see any issues with your WinMTR. The high latency that you are seeing on the as57976.net nodes is actually normal and is happening due to those routers giving less priority to ICMP packets which is what the test uses.