Respawn, the creators of Titanfall 2 somehow managed to make completely inconsistent Double jumps in Apex.
They all use the same 2 second cooldown.
But only Sparrow and Seer get an indicator showing you that.
Wraith’s and Seer’s don’t give you any height if you try to use them after a Wallbounce or other height gains.
Axle’s only works if you leave the ground with a jump. If you slide of an edge it won't work. All the other double jumps do work in that case.