This is a fairly simple bug. As per Xanathar's Guide to Everything, the Mastermind rogue archetype's "Master of Tactics" trait text reads:
Master of Tactics
Starting at 3rd level, you can use the Help action as a bonus action. Additionally, when you use the Help action to aid an ally in attacking a creature, the target of that attack can be within 30 feet of you, rather than within 5 feet of you, if the target can see orhear you.
But a mastermind rogue character shows the following text on the Actions page of its character sheet:
Master of Tactics
You can use the Help action as a bonus action, and when you use the Help action to aid an ally in attacking a creature, the target of that attack can be within 30 ft. of you if it can see andhear you.
As you can see from my highlighting, the description from the character sheet varies importantly from the Xanathar's description by one word: "and". It accidentally imposes an extra restriction on being able to use this trait, requiring that the target be able to see and hear the mastermind character. The fix should simply involve changing the word "and" to the "or" found in the Xanathar's description.
This is a fairly simple bug. As per Xanathar's Guide to Everything, the Mastermind rogue archetype's "Master of Tactics" trait text reads:
But a mastermind rogue character shows the following text on the Actions page of its character sheet:
As you can see from my highlighting, the description from the character sheet varies importantly from the Xanathar's description by one word: "and". It accidentally imposes an extra restriction on being able to use this trait, requiring that the target be able to see and hear the mastermind character. The fix should simply involve changing the word "and" to the "or" found in the Xanathar's description.
Thank you! I will pass this bug on to the proper team.