Deriving a sum of two matrix norms erroneously returns 0

[sdall]

SymPy 1.12 returns an unexpected matrix derivative.

from sympy.core.symbol import symbols
from sympy.matrices.expressions.matexpr import MatrixSymbol
from sympy.matrices.expressions.trace import Trace

m, n, k = symbols("m n k")

A = MatrixSymbol("A", n, m)
U = MatrixSymbol("U", n, k)
V = MatrixSymbol("V", k, m)

def nrm2(e): 
    return Trace(e.T * e)

# works 
(0.5*nrm2(A - U*V)).diff(U) 

# works
0.5*nrm2(A - U*V).diff(U) + 0.5*nrm2(A).diff(U)

# does not work (returns 0)
(0.5*nrm2(A - U*V) + 0.5*nrm2(A)).diff(U)  

# does not work (returns 0) 
(0.5*nrm2(A - U*V) + 0.5*nrm2(U)).diff(U)