Strange behavior of simplify.

[PhyX-Meow]

Hello, I'm using Symbolics.jl to do some expression calculation, but today I found simplify function not work in case.
Run these code

@variables x,y,z

f = 4/(1-x^2-y^2-z^2)^2
D = Differential(x)

fx = D(f) |> expand_derivatives |> simplify

gives

2x*(2 - 2(x^2) - 2(y^2) - 2(z^2))*(4 / ((1 - (x^2) - (y^2) - (z^2))^4))

The fraction is not canceled

However after I copy and paste then do simplify again:

julia> 2x*(2 - 2(x^2) - 2(y^2) - 2(z^2))*(4 / ((1 - (x^2) - (y^2) - (z^2))^4)) |> simplify
(16.0x) / ((1 - (x^2) - (y^2) - (z^2))^3)

One see the desired fraction cancelation.
What's wrong here, shouldn't they be the same expression?

[PhyX-Meow]

Forgot to say:
Julia version 1.8.3
Symbolics v4.13.0

[PhyX-Meow]

Well...This seems to be fixed in latest version. Closing...