Right now the item choice advancement doesn't properly check to see if choices made at a later level are invalidated when a player uses Modify Choices to change something they choose at an earlier level.

Possible to select a non-repeatable option more than once

1. Take Pact of the Blade at Level 1.
2. Advance to Level 2.
3. Choose Armor of Shadows and Eldritch Mind.
4. Modify Level 1 choices.
5. Swap Pact of the Blade for Eldritch Mind.
6. Observe the character now has two Eldritch Mind features.

Possible to retain a dependent option if its prerequisite is changed

1. Take Pact of the Blade at Level 1.
2. Advance to Level 5.
3. Take Eldritch Smite and Thirsting Blade.
4. Modify Level 1 choices.
5. Swap Pact of the Blade for Eldritch Mind.
6. Observe the character retains Eldritch Smite and Thirsting Blade.