Correction Needed?[]
The game file (statuseffects.GameDataBundle) says,
"ApplicationBehavior": "UseLongerDurationIfAlreadyApplied",
so it's unlikely that it stacks with itself as stated in the article.
(look for "DebugName": "Mace_Rending_Smash_SE_ArmorRating",) 92.22.105.129 19:07, 20 May 2021 (UTC)
- Tested this just now and yes, it does not stack with itself, even from different sources - it just renews the timer as you mentioned.