Platform, device and operation system
Android, Samsung S9
What were you expecting to happen, and what actually happened
When you equip 2x rings, ex 2x Firewalker Rings, 2x Runic Rings, 2x Bone Rings, etc - they should count as 2 separate items for Set bonuses. Currently, if you only have, say, 2x Runic Rings, you do not get the 2 piece Runic Set bonus.
How often does this happen? When did it begin happening?
Constant. Patch 0.37
Steps to make it happen again
See steps above.