ring regression in v4.19.0-rc2

Stream: mathlib4

[Yaël Dillies]

The following used to work. Since bumping to v.4.19.0-rc2 (or around), it doesn't.

import Mathlib.Tactic.Ring

example (ε : ℚ) (n : ℕ) : (ε / 2) ^ n = ε ^ n / 2 ^ n := by ring

[Yaël Dillies]

It looks like the / 2 in the LHS becomes the 1 / 2, while the one in the RHS becomes the atom 2⁻¹