Atzoatl Temple: Temple Nexus didn't "upgrade all adjacent rooms by 1 tier regardless of connections"

Before itemizing the Temple, the two III's were already III's.

The Jewellry Forge and the Hall of Locks were I and II, or II and I (I forget which was which).

Post-itemizing, only the I became a II. The II other one did not become a III, it stayed a II.