This is an AWS credit warning – nothing to worry about. For some reason Mendix starts tracking it immediately on startup which I imagine will always prompt a warning.
In simple terms AWS manages CPUs as a cloud platform therefore it could be using some of your CPU for other Apps while you’re not using it in exchange for credits. Once your CPU hits maximum usage AWS converts those credits back into CPU power and you end up using CPU power from other apps in order to process data quicker – of course in exchange for credits.
Update: Extracted the CPU credits documentation from the discussion linked below: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/burstable-credits-baseline-concepts.html – Thank you Pim
Hope this helps