Oil spec

Maybe for some reason 0W20 was not available so they used the more common 5W30. It won't blow up but it would probably be a good idea to do another service when you can using the correct oil.
Hopefully that's all it is and it wasn't for nefarious reasons like trying to cover up oil consumption.

If you are worried that the wrong oil damaged something: mine was used with 5w-30 in it's whole life (a bit more mileage than yours). 6 months ago I changed oil with 0w-20. There is literally 0 oil burning, and I use it daily, almost 60km (37 miles) every day.

The real question is, did they try to cover up something with that oil? I advise you to change it and use the correct oil just to see if it burns the thinner oil or something. But I have a feeling that they just didn't have the correct type. Also, a little burning it pretty normal.