I have 59 INT and taken following nodes:

Necromancer:Ward Vortex, which states “50% increased ward Retention”;

Acolyte:Unnatural Preservatoin, which states “grants 25% ward retention”;

Lich:Mental Cacophony, which again, states “grants 25% ward retention”;

My ward retention is 457%

Now there are 2 ways to interpret these nodes: add or multiply.

assuming all add: 59*4+25+25+50 = 336%
assuming all multiply: 59*4

*200% = 472%*

assuming 50% add and 50% multiply: (594 + 50) * 150% = 429%

assuming 50% add and 50% multiply: (59

assuming 25% add and 75% multiply: (59*4 + 25) * 175% = 456.75%

Now this is a problem because both 25% nodes say “grant 25%”, but one of them adds and the other multiplies.

Update: I have rolled a new character and found out that adding 1 point to Unnatural Preservation increases Ward Retention by flat 5%, so it’s the additive passive. (I had 8 INT, so multiplicative would’ve given only 2%).