This happened me today for the first time. I had never seen this before.

Here is the rule:

IFP Official Tournament Rulebook

Section 12. I. (p.38)

“The Net Posts. The net posts are positioned out of bounds. If a ball strikes the net post or anything attached to the net post, it is a fault and a dead ball is declared. This rule does not include the net, the net cable, or rope between the net posts.”

I errantly thought that the ball would be in play and good. This is not correct regarding the Net Post. If it hits a part of the net post (which should be out of bounds), then it is a fault and the player or team of the player hitting that ball loses that service. Who knew? [edited July 10, 2017 to correct an error]