I see this error in most environments I look around in and have never really looked into the warning before. After doing some research on the topic and seeing what people at Microsoft have to say, it seems you can quite happily ignore this error. – I’ll update this if I find anything else regarding this error in the future.
To quote one of the Microsoft guys from technet:
When a Worker process shuts down due to lifetime timeout, this event log warning is logged. This warning is normal, you don’t need to worry about it.