It could be that Spunky is going through a moult. My Boris - house pet budgie - was pure blue on the cere until the 2nd moult. Then "he" turned out to be a she! I was devastated, can't name a girl budgie a boys name - but she refused to answer to anything else so the name is stuck forever. Wait until Spunky's moult is over. It could just be the cere getting reading for adulthood.
To see how confusing it can get, have a look at Lady's Budgie Cere post (above this one), some you'd swear were boys are girls!