Congrats. Mine have done it numerous times. I'm not so sure what triggers flower stalks, but I remember doing a big water change and a bunch of my anubias started growing stalks. I had three stalks that suddenly appeared and within a few days they bloomed nearly at the same time. Cool experience.. glad yours decided to flower for you. I heard it is a bit rare for anubias to bloom.. and if they do, you're lucky.
55 gallon Rainbowfish species/Harlequin rasboras community Dutch scape low-tech planted tank
60 gallon Bala shark low-tech planted tank
250 gallon Community Tiger Oscar/Red hook silver dollar/Silver dollars/BR Parrots/ PB Jack Dempsey/Clown loaches/Tinfoil barb/Roseline sharks/Barbs Monster fish tank