I haven't had time to check this, but from man procmailex
Forward all mail from peter about compilers to william (and keep a copy of it here in pet-compil).
The main difference to yours is the '*'. In the procmail examples it is used in a regex, ie with the preceding character which is a '.' and means 0 or more of any character (except a new-line). You have used the * the same way as a file system glob, ie as a multi character wildcard. Try using the following as your search string: