This issue caused by platformer behaviour that doesn't have a feature called "tolerance jump". Just like what you suspect the Player didn't jump at right moment immediately on tip end of solid. Naturally user tends to react too late that he got the Player already fall before user able to hit jump button. To counter this, developer create mechanism that compensate user response that giving "forgiveness" to the Player so it still can jump with some tolerance of time & distance since it fell.
In Construct we must activate this "tolerance jump" by enabling double jump. If you don't want extra jump while in mid-air, you can limit it by add condition perhaps a variable to strict how many times Player can jump again after "first" jump.