Also not uncommon going the other way too. NATO countries will commonly station just a few soldiers in countries like Estonia. It’s trip wire kind of thing, it means if Russia attacks that country then there will immediately be soldiers from many different NATO countries (even just a few soldiers each) fighting to defend the country on day one.
There’s more than just a handful of soldiers from each NATO countries in the Baltic countries now to deter Russia from doing something stupid. And it doesn’t make sense for Estonia to deploy a lot of their military to the Red Sea given the situation with Russia. So they send one soldier as a statement that they support the operation, they simply don’t currently have the military resources to contribute significantly.
The tripwire concept applies here too, an attack on a ship that soldier is on is an attack on Estonia. Doubt that will deter the Houthis (they’re psychos) but it’s still a show of support.