What bugs cause cloud production incidents?

This is a study of every high severity production incident at Microsoft Azure services over a span of six months, where the root cause of that incident was a software bug. Software bugs are the most common cause of incidents during this period, accounting for around 40% of all incidents (so we can infer there were around 280 incidents total in the pool). 7% of all software bug incidents are caused by mistakes in constants: hard-code configuration, special purpose strings such as URLs, and enum-typed values.

Source: blog.acolyer.org