In-Place Operations (+=, -=, /=, *=) Yield Incorrect Units

While migrating Elephant to numpy >= 2.0 we discovered the following bug, where in place basic operations +=, -=, /= and *= result in incorrect units.

Minimal example to reproduce:

a = 5 * pq.s
b = 6 * pq.kg

a /= b  # results incorrectly in a = 0.833 * s

a = a/b  # results in a = 0.833 * s/kg (expected)

With:

• Python 3.13.1
• quantities 0.16.1