EDITED TO ISOLATE ISSUE WITH PASSIVE POWER ONLY:
I did 2 trials. In one trial, the damage boost from Juggernaut’s passive did not apply to a black match. In the other trial, it did apply to a blue match. Full details below. Both matches were the first match made after entering battle. Both matches were made by Juggernaut. Both matches were against a PvE team of Hood + 2 goons with Hood in front.
Running a team of 4 * Rocket, 4* Star-Lord, and 4* Juggernaut in the Unholy Alliance segment of the Hearts of Darkness PvE.
My 4* Juggernaut is level 250, 4/3/5. The relevant power is:
Red: “(PASSIVE) One does not simply stop the Juggernaut. Juggernaut’s base match damage is increased by 65%…”
With my level 294 Rocket plus the other GotG member, he lays out 7 Strike tiles at the start of battle of strength 318 (total additional of 2226).
Juggernaut’s base Black damage is 21.
First match is a Black match 3 by Juggernaut. It did not contain any strike tiles and did not cause any cascades.
The match did a total of 4715 damage to the enemy in front and 2426 to the 2 enemies behind.
The enemies behind were damaged by his Green power for 200 added to the strike tiles 2226, for 2426 (as expected).
For the enemy in front, 2426 of the 4715 is accounted for as described in the preceding paragraph from his Green power, that leaves 4715 - 2426 = 2289 to account for due to the initial match. If 2226 of the 2289 initial match damage is from the Strike tiles, that leaves 63, which is 3 x the base Black damage of 21. So the damage boost from his Red power is not being added, or it would be 21 x 1.65 x 3 = 104.
I have videos supporting both the black not working and the blue working I can post (if I can figure out how).