As I understand it, this has nothing to do with Lebanon.
It has to do with ships moving through the Oman side of the strait. Iran is unhappy with that, because the want to control all the movement through it.
@timming is right. This particular incident was triggered because Oman announced a parallel route in Strait, and some ships were lead to believe that you don't need to talk / coordinate with Iran to use this new route. See this thread for more details - https://news.ycombinator.com/item?id=48692620