The Mono project used to have LGPLed libraries. In fact
mbundle still says when you run it
Note that statically linking the LGPL Mono runtime has more licensing restrictions than dynamically linking. See http://www.mono-project.com/Licensing for details on licensing.
As of March 2016 they re-licensed them under MIT. Given the project is many years old and probably has contributions by many outside contributors and those contributions were only provided as LGPLed contributions how were the able to change the license? Wouldn't they have had to get permission from every contributor for the last 12 years? Maybe those contributors had to sign some agreement?