The Potion of Relentless Striking appears to show oddly inaccurate information in its tooltip next to the imbiber's portrait:
Guess that should be, according to the item's description, +50% Action Speed*, +20% Melee Damage, -10 Deflection.
* make sure you check the signage convention here. Bonuses should consistently carry a minus, since they're making stuff take less time.
Edited by AndreaColombo, 27 November 2017 - 06:16 AM.