Getting inconsistent matrix multiply results from Flux.Dense function

gistfile1.txt

using Flux
using Random
Random.seed!(12345)

function showdiff(f, n)
    a = rand(Float32, n, n) # shape (n,n)
    b = rand(Float32, n, n) # shape (n,n)
    c = cat(a, b; dims=3)   # shape (n,n,2)
    a_out = f(a)            # shape is (n,n)
    c_out = f(c)[:,:,1]     # shape is (n,n)
    diff_coord = findfirst(iszero, a_out .== c_out)
    if !isnothing(diff_coord)
        return "$(a_out[diff_coord]) !== $(c_out[diff_coord])"
    end
    nothing
end

n = 8
d = Dense(n, n)
showdiff(d, n)

VERSION
import Pkg
Pkg.installed()["Flux"]