On two different machines alsamixergui shows the same behavior. After startup (displaying the correct set of controls) it is simply stuck and consumes 100% CPU. It does not respond to any input. Only killall alsamixergui stops it. Whereas the first machine had this package installed for months the fresh install on a second machine shows the same behavior. There are no additional log messages. Started it from a terminal with the same result. It also lacks a verbose or debug option.
Created attachment 824497 [details] emerge --info