A friend today told me that the word חשמונאי traditionally pronounced "Chashmonai" should really be pronounced "Chashmunai" with the vav being read as a shuruk vowel instead of a cholom.
Is this true? How would one know? And if so, when and why did it change?
NOTE: Since this is an issue where many people feel very connected to their received pronunciation, a clear online source that anyone can read is highly recommended.