When using a Victory Talisman and a PvP Gold Boost, I am having the same issue as the OP.
I should have received 81 XP, and I am getting 2 XP when a Victory Talisman is equipped and a PvP Gold Booster is active. I have not tried it with a different Talisman.
If I don’t use a PvP Goold Boost, and equipping only a Victory Talisman, I receive the correct amount of XP: 81.
EDIT:
I also had 2 Buffs ( Mad Mage’s Ruin and Old God’s Shrine ) active alongside the Gold Booster.
Android 14, Samsung Galaxy A13.
Region: Geheron, Brown, Bloody Frenzy Active.