It has been like this for ages where you activate class ability on warlock, rift animation takes place but the rift doesn't go onto the ground because of the tiniest bit of uneven geometry or because of your movement before placing the rift or because the game feels like not letting you place the rift because you committed a thought crime against the game. For example on the Grasp of Avarice final boss at the debuff deposit crystal you have to do maths in order to figure out if your rift will actually place on the ground. Also happens all the time in crucible if there is a tiny bit of geometry behind cover where you want to rift you'll waste time placing rift and it won't be on the ground. Super super frustrating