With Bastion, the grenade jump will become directional as soon as you move away from the grenade spot (stuck on the ground below you) even a tiny little bit.
That’s fine, as long as you can still consistently perform a perfectly straight, non-directional grenade jump by standing still, sticking a grenade exactly below you, and jumping straight up when it explodes.
(it would be much more user-friendly if it was made far easier to do this without forcing you to stand still, by enlarging the area where the grenade jump remains straight, or even making the momentum boost directly dependent on your own movement, i.e. even if you’re far away from the grenade, if you stop moving and just jump, it would still boost you straight up, non-directionally - but that’s a gameplay topic, and it can be fine even if it forces you to stand perfectly still, especially if that’s intended as a nerf to Bastion’s mobility)
However, what’s not fine, extremely annoying and i believe can be considered a bug, is that even when you stop moving completely, stick the grenade perfectly below yourself, and jump straight up, the jump boost will become directional as soon as the ground you’re standing on is slanted even a tiny little bit, which is the case in a wide variety of map locations and you cannot even notice it at all.
It’s easy to test this in the Practice range: the ground is perfectly horizontal in the area up the small staircase to the left of your spawn, but just behind the ultimate token there are some snow mounds where you can see how even at the very beginning of the mound where the ground visibly still pretty much looks horizontal, your grenade jump will become directional without you being able to do anything about it.
Bastion is one of my favourite heroes to play and i especially like his recon gun the most out of all weapons in the game (long-range stable tracking), but this issue that greatly affects his mobility is gamebreaking enough on basically every map that it makes the hero unbearable to play, so please address this.