Why are there such different UGate and U3Gate implementations in the Qiskit documentation?

The documentation for the new version Qiskit 0.20.0 states that:

• UGate is "Implemented using two X90 pulses on IBM Quantum systems:

$U(θ,ϕ,λ)=RZ(ϕ−π/2)RX(π/2)RZ(π−θ)RX(π/2)RZ(λ−π/2)$"

• U3Gate is "Implemented using two X90 pulses on IBM Quantum systems:

$U3(θ,ϕ,λ)=RZ(ϕ)RX(−π/2)RZ(θ)RX(π/2)RZ(λ)$"

It looks like only the latter matches the known rotation sequence for U3:
$z$-rotation ($lambda$), $y$-rotation ($theta$), $z$-rotation ($varphi$)

Although their presentation matrices completely coincide:
$$
mathrm{U3}=
mathrm{U}=
begin{pmatrix}
cos(theta/2) & -mathrm{e}^{ilambda}sin(theta/2)
mathrm{e}^{iphi}sin(theta/2) & mathrm{e}^{i(phi+lambda)}cos(theta/2)
end{pmatrix}.
$$

Is this an inaccuracy in the documentation or am I missing something and these gates are actually different?

Just in case, the aforementioned difference stated in the documentation refers to the hardware (not software) implementation of these gates on IBM Q systems.