[PoE2] Ruthless support gem increasing stun by 5% instead of 500%

Ruthless support gem says "Every 5th use of supported skill increases stun build up by 500%.".
However, when equipped, it shows this on the skill stats screen:
"More Stun Buildup on every fifth use 5%".

In addition to this, the Overpower gem which is supposed to add +50% Stun Buildup, appears to do nothing.

Also the Quarterstaff attack skill Wind Blast says it's supposed to do 150% more Stun Buildup, but the dps breakdown shows it just doing the base 100%.

Feels a lot like someone fudged a decimal point somewhere and all Stun modifiers are being divided by 100.

Found this looking for the same thing noticing Ruthless only showing as 5%.

My experience in game is that it's probably working correctly as I notice a massive stun increase every few hits.

Not so sure about Overpower, you are right it doesn't display but harder to tell if it's actually working or not.