According to my test results, I didn't encounter with any issue. Effect is properly increasing dexterity and physical critical damage as description pointed.
Greetings.
Hello,
I think you are misunderstanding the phrase "physical critical damage". You marked in your pictures the "physical damage" and the "critical hit rate". But neither one of those is infected by the buff. The buff increases your "critical damage" which literally means that your critical hits on mobs can deal more damage. This is something which, as far as i know, is not displayed in the character window. (maybe this could be added in the future)
Hope i could help to clear this up.
Kind regards Nghty
Thank you for the explanation.
No Problem 
Thats why the game has this forum.
So, there's a chance that units will suffer 30% more damage in a critical hit?
And yes, you are correct.. With the buff, the mobs will suffer the ~30% more dmg from a critical hit than without the buff.
Regards Nghty
Or with a 30% chance of additional damage in a critical hit? That is every third blow somewhere.
I dont think it works like that.. When with 30% chance of more damage like every third hit, how would you explain the ~80% from each of your ring?
I think that every critical hit since lvl 1 does a certain amount of damage more than a non critical hit... and the percentages from buffs/equipment are just boosting the amount of critcal damage even further.
(Please correct me if i am wrong )
Regards Nghty
That's a good question. Unfortunatly I can't help you with that because i don't know the formula to calculate the damage.
Maybe a Dev can enlighten us 
.
Regards Nghty
Physical critical damage is increasing critical portion of your damage.
Which means if your skill is inflicting 100 damage without critical and 130 when it is critical, 100% critical damage boost should make it 160.
Greetings
Sorry if I correct you, but if a skill is inflicting 100 damage without critical and you have a 100% crit damage boost, the skill will inflict 230 damage.
That's because the base crit multiplier is 30% (if you did not changed it from base game ) and with another 100% boost, you have 130% crit boost (crit values are additive).
And 130% crit means: base damage (non crit) * 2.3 because the base damage is increased by 130% with a critical hit
Kind regards
