The bug
Tamed wolves no longer attack armor stands as of Java version 1.20.5 and onwards, due to this "bugfix" : MC-172047
I can't think of a situation in which dogs attacking armor stands could be unwanted behaviour or a disruptive bug. Armor stands are entities that are perfect to serve as dummies for combat scenarios and dogs should be able to attack them. Fixing this bug provides consistency with dogs attacking other entities that their owner attacks (such as zombies).
Dogs being able to attack armor stands used to be a very niche but very interesting mechanic to make a player specific detection system (attachment provided) and this bug breaks this awesome and unique mechanic.
MC-172047 was mistakenly seen as a duplicate bug to MC-195384 which is a valid bug fix that should remain unchanged.
To reproduce
1. Tame a wolf
2. Attack an armor stand
→ Tamed wolf doesn't attack the armor stand that you attacked.