yes this is typical. One of mine did this instead of producing a flower. it did go on to flower a few months later.

Phalaenopsis like to tease you. They can start a new root, new leaf, or send out new buds part way up a stem, while in bloom, or add them on the end. If my spent stems keep their colour I leave them to see if this happens. Only for a while though. They are a very rewarding houseplant. The only one I get on with. My labels seem to say you get a flower every 6/12