Michael Van Biesbrouck
No, Prometheus always builds after moving unless winning or another power (Hecate, Tartarus) causes the turn to end early.
In the Deluxe Edition, we are going to introduce a new way to write some powers that will make Prometheus more clear. Sneak peek:
Deluxe Prometheus wrote:
Alternative Turn: One of your Workers builds, moves and builds again. Your Worker cannot move up.
Deluxe rules wrote:
Alternative Turn: Instead of your normal turn, you may take the alternative turn described; the abilities and restrictions do not apply to normal turns.
We hope that this formatting will end all questions about Prometheus and a few other powers.