Is the w₀w_a CDM cosmological parameterization evidence for dark energy dynamics partially caused by the excess smoothing of Planck CMB anisotropy data?

We study the performance of the spatially flat dynamical dark energy w₀w_aCDM parameterization, with redshift-dependent dark energy fluid equation of state parameter w(z)=w₀+w_az/(1+z), with and without a varying cosmic microwave background (CMB) lensing consistency parameter AL, against Planck CMB data (P18 and lensing) and a combination of non-CMB data composed of baryonic acoustic oscillation (BAO) measurements that do not include DESI BAO data, Pantheon+ type Ia supernovae (SNIa) observations, Hubble parameter [H(z)] measurements and growth factor (fσ₈) data points. From our most restrictive data set, P18+lensing+non-CMB, for the w₀w_aCDM+A_L parameterization, we obtain w₀=-0.879±0.060, w_a=-0.39_-0.22^+0.26, the asymptotic limit w(z→∞)=w₀+w_a=-1.27_-0.17^+0.20, and A_L=1.078_-0.040^+0.036 (all 1σ errors). This joint analysis of CMB and non-CMB data favors dark energy dynamics over a cosmological constant at ∼1σ and AL>1 at ∼2σ, i.e. more smoothing of the Planck CMB anisotropy data than is predicted by the best-fit model. For the w₀w_aCDM parameterization with A_L=1 the evidence in favor of dark energy dynamics is larger, ∼2σ, suggesting that at least part of the evidence for dark energy dynamics comes from the excess smoothing of the Planck CMB anisotropy data. For the w₀w_aCDM parameterization with A_L=1, there is a difference of 2.8σ between P18 and non-CMB cosmological parameter constraints and 2.7σ between P18+lensing and non-CMB constraints. When A_L is allowed to vary these tensions reduced to 1.9σ and 2.1σ respectively. Our P18+lensing+non-CMB data compilation positively favors the w₀w_aCDM parameterization without and with a varying AL parameter over the flat ΛCDM model, and w₀w_aCDM+AL is also positively favored over w₀w_aCDM.