Distortion is unreasonably too weak!
The killer's power should basically match that of four efficient survivors, and so a killer perk should have four times the strength of the opposing perks of the survivors, meaning that all four survivors must equip a given perk to neutralize that of the killer.
If we analyze BBQ and Chili, we notice that it offers up to a maximum of 2 * 4 * 3 = 24 Aura readings (provided that each survivor is hooked twice before someone dies and, at each hook, the killer sees the Aura of the other three people), plus 3 other Aura-readings at the first survivor's sacrifice, 2 at the second survivor's sacrifice and 1 at the third survivor's sacrifice; total: 24 + 3 + 2 + 1 = 30 Aura-readings of the survivors, in optimal conditions, the best possible. Well, if all four survivors used Distortion, each would have 3 protections from the reading of their Auras, that is 3 * 4 = 12 shields, and 12 is equal to 2/5 of 30. As you know, BBQ can be countered by hiding in a locker, crouching behind an incomplete generator or approaching less than the minimum activation distance (in worst cases, 40 meters), or bypassed by simulating a direction and turning sharply after a few seconds. I chose BBQ because it is easy to calculate its maximum power, in ideal conditions, and compare it with that, absolutely inadequate, of Distortion.
However, there are dozens of Aura reading skills that cannot be prevented without Distortion, or that even destroy the Distortion tokens without the player having any possible defense. Some examples:
1) Freddy's dreamworld;
2) Bitter Murmur (you can't stop making gens!);
3) A Nurse's Calling with a stealthy killer;
4) Deerstalker (issue just fixed);
5) an avalanche of killer's add-ons.
Here you will find an exhaustive list: https://deadbydaylight.gamepedia.com/Auras
Evidently, Distortion is an absolutely weak, seriously insufficient perk. It would be very reasonable and balanced to buff Distortion in ONE of the following ways:
1) tokens are 4/5/6;
2) tokens can be recharged with some simple actions;
3) the survivor can decide, at their sole discretion, when to activate the shield of Distortion and when instead let the killer see their Aura to save tokens;
4) if the solutions 1), 2) and 3) are rejected, at least the three tokens must grant three effective protections, that is Distortion doesn't trigger in any of the following circumstances (aside when you are dying or trapped some way): a) the survivor is asleep or b) the survivor's Aura is outside the killer's field of view (for example, you heal yourself within 28 meters from a crouched Pig with A Nurse's Calling, but you are behind her, so you don't need Distortion to remain hidden).