Looking at your pics & game stats, it appears that:
1. You got both the Lord Of Wolves & Black Talon catalysts.
2. You completed the LoW catalyst requirement (which erroneously awards the BT catalyst triumph), as you’ve gotten many LoW kills recently.
3. With the new catalyst, it won’t let you slot into weapon until you get the required kills with the weapon.
Aaah so that's why it's showing up as completed. Well guess it's another grind then... hope the triumphs get fixed. There's also 2 triumphs listed for worldline zero catalyst.