Confirming Tri Attack. It's a 20/3 % chance per status infliction.
I'm also getting a similar result to Poccil - the Custap effect is still carried out despite not having a custap berry when Tricked
EDIT: oh, if it switches out, it does not retain its Custap effect.
What I did was this;
Custap Salamence vs Slowbro
Salamence used Double Edge! (health bar goes red)
Slowbro used Trick
Salamence switched out then switched back in.
Slowbro switches for Jolteon.
No mention of Custap as Salamence attepts to Draco Meteor (but gets Tboled by Jolteon)
Also, another question. If Custap is knocked off after it's effect would be "triggered" via falling under 25% (Double Battle for example), does it's effect disappear as well? I ask this because it has already been discovered that the Custap user can consume "no item" if it has tricked no item by another Pokemon.
I Knock Offed a Custap holder, and Custap was not consumed and the effect did not take place.