Note: all of these were tested with 17 STR (1.0425 buff from STR) and a 100 fixed damage weapon.
-The "Seethe giving less Vengeance" thing has been long reported, but putting it here for consolidation.
Heavy Slash seems to have hitbox issues. It fails to hit enemies such as the Mimics in LotMM, Ambush Drakes, or some tiny spiders. See posts below on which enemies this issue occurs on. Reave has a similar issue to a lesser extent.
-Heavy Slash base damage is 80 magnitude rather than stated 100.
-Heavier Slash still gives two procs, one for 280 magnitude damage and a follow up for 80.
-Landwaster gives ITF the effect of setting your Vengeance to 50%.
-Landwaster only works if you have Bloody Reprise.
-Momentum seems to affect mount speed, unsure if placebo effect or not.
-Momentum only grants its "+200 magnitude/no knockdown" Bull Charge bonus if you have the Momentum run speed bonus (ie, run around in circles for a bit if you want the bonus).
-Prepared Slam only works on Shield Slam.
-Shockwave has a base damage of 1100 magnitude rather than its stated effect.
-Commander's Strike doesn't benefit from the damage bonus of STR.
-Commander's Strike also gives a 10% debuff rather than a 5% debuff.
-Shield Thrower reduces the base damage of Shield Throw to something like 135 magnitude rather than the stated 250.
-Cleaving Bull can proc off of Enforced Threat, but Cleaving Bull off of ET strangely does 0 damage.
-Rising Tide also procs off of ET, but strangely does 0 damage as well.
: Vanguard Dig In has a bug that makes you permanently have block up even when doing other actions like using powers, makes using retaliate impossible. Swapping to Dreadnaught while this bug is active makes Dreadnaught use Retaliate automatically without blocking.
If people find more, or new ones pop up, I suppose you can post it again on this thread.