Paragon's Guard (fighter feat 12th) or Shield Paragon (champion feat 20th), with a tower shield?

[Colette Brunel]

Paragon's Guard (fighter feat 12th) and Shield Paragon (champion feat 20th) allow a character to constantly have their shield raised. Tower shields say, "When you have a tower shield raised, you can use the Take Cover action (page 471) to increase the circumstance bonus to AC to +4. This lasts until the shield is no longer raised." Take Cover says, "This lasts until you move from your current space, use an attack action, become unconscious, or end this effect as a free action."

If a character has Paragon's Guard or Shield Paragon, they Take Cover using their tower shield, and they use an attack action, are they still gaining the +4 AC?

[CyberMephit]

It all depends on what is meant by "This". I would say that in the shield description "This" is the ability to use the Take Cover action, not continuing to benefit from it - as the latter is already defined under Take Cover itself.
Thus, the stance benefit is that you need one action to Take Cover behind your shield, not two (in addition to gaining the normal AC and shield block).
And with or without the feat, you still lose the cover once you hit any of the triggering conditions - be it from Take Cover or from Raise a Shield or ending the stance.