A tech situation is when a character can "tech" by pressing shield right before they hit the ground, allowing them to immediately get back up in-place, to the left, or to the right.

In Smash 4, you can tech after being footstooled. In Smash Ultimate, you cannot tech after being footstooled.

In this clip here, after Sheik gets footstooled, she doesn't tech: She bounces with her back on the ground (bouncing on your back/front is the animation you get when you don't tech), then uses get-up attack (you can't use get-up attack out of teching).

So there's no incongruence here. Ultimate was confirmed to have no teching out of footstool, and this clip shows Sheik not teching out of footstool.