That's some ebb and flow and occurs occasionally to you.
It's once in a while increased, but also ebbs down again.

I absolutely love exploding skeletons. Not only do they basically spawn gunpowder kegs for you (shoot them in the legs: it doesn't set off the keg), but you can also easily use them to wipe whole squads of other skeletons. You can use this to quickly turn bosses into bonemeal too

Just learn where the ammo boxes are on each islands and gunpowder skeletons will become your best friends

Yeah I've had it hapen too, it's fun for a while but I feel forced to equip either a pistol or eye of reach to deal with this and I'm kind of liking the Blunderbuss now that it's the only weapon with knockback.

I've had a couple of instances in the past few games I've played where five have appeared at once - it's usually when I'm not on a voyage. Great for target practice!

I've noticed this as well. I don't think they're as prevalent as they were when they were introduced, but they do seem to be turned up a bit.