What does this light blue tile mean?

Occasionally while doing the Tempest Trials (I don't think its specific to that, but it's where I've been noticing it happening), I see a light blue tile when trying to move a unit. It happens with Sonya most, if not all, of the times I've seen it. For reference, this is what I'm referring to (the square directly above Sonya):

What does this tile mean? I don't think it represents a tile I can attack from, because it doesn't show up in most other cases where this would be applicable.

Solution 1:

A light blue tile is a tile that your hero will be utilizing one of their abilities/passives to move to.

One example I can immediately recall is Wings of Mercy, though I'm not sure what ability/passive is triggering in your screenshot.