As the one and only vehicle in Fortnite: Battle Royale, the Shopping Cart already has a history bumpier than a ride in one down a mountain. Shopping Carts were added to Fortnite in late May, but within the several weeks they’ve been in the game so far they’ve already been pulled twice.

Are they still in Fortnite right now?

Yes! Epic Games reintroduced Shopping Carts to Fortnite: Battle Royale on Tuesday, June 26 at roughly 11:25 a.m. Eastern after the developer had pulled the Carts more than once already.

But why do Shopping Carts cause so many problems and get pulled from Fortnite so frequently?

Keep in mind that Fortnite is still, after all this time, in its “Early Access” period. It’s exceedingly uncommon for an early access game to get this popular, but the term basically means that Fortnite is an incomplete game. Plenty of games out there use extended early access periods to get more players into the game to find bugs and test things out. The full, complete version of a game comes muchlater.

So if players are ever looking for a reason as to why servers go down or glitches like the ones related to Shopping Carts happen, that’s the most probable explanation.

For now, be thankful that Shopping Carts are back.

Epic Games previously removed Shopping Carts from Fortnite on the afternoon of Wednesday, June 20 at 1:45 p.m. Eastern. The company cited “ongoing issues” as the primary reason. This came less than three hours after the Carts were reintroduced to the game after their removal on June 16 “due to a bug.”

Epic Games hasn’t elaborated on the exact nature of the bug causing these problems, but it could be related to how players have used Shopping Carts to launch incredibly high into the air or that they’ve been used to enter inaccessible parts of the map, like that creepy underground hatch.

So it’s hard to know exactly why the Shopping Carts cause so many issues, but we can make some educated guesses.

Keep in mind that the Shopping Cart is Fortnite: Battle Royale’s first and only vehicle. Unlike other battle royale games like PUBG, Fortnite: Battle Royale wasn’t designed with vehicular transport in mind. So the game’s physics engine may have a hard time handling how the carts function in-game.

There’s a reason why developer Epic Games went with a Shopping Cart instead of a car, ATV, or even go-kart. They’re simple, and even then, they still cause plenty of problems.

Chances are we might never see another vehicle in Fortnite: Battle Royale, but at least the Shopping Carts have returned for the time being.

This article was updated from its original version, which was first published on June 20.