  We test the BUQEYE model of correlated effective field theory (EFT)
truncation errors on Reinert, Krebs, and Epelbaum's semi-local momentum-space
implementation of the chiral EFT ($\chi$EFT) expansion of the nucleon-nucleon
(NN) potential. This Bayesian model hypothesizes that dimensionless coefficient
functions extracted from the order-by-order corrections to NN observables can
be treated as draws from a Gaussian process (GP). We combine a variety of
graphical and statistical diagnostics to assess when predicted observables have
a $\chi$EFT convergence pattern consistent with the hypothesized GP statistical
model. Our conclusions are: First, the BUQEYE model is generally applicable to
the potential investigated here, which enables statistically principled
estimates of the impact of higher EFT orders on observables. Second, parameters
defining the extracted coefficients such as the expansion parameter $Q$ must be
well chosen for the coefficients to exhibit a regular convergence pattern -- a
property we exploit to obtain posterior distributions for such quantities.
Third, the assumption of GP stationarity across lab energy and scattering angle
is not generally met; this necessitates adjustments in future work. We provide
a workflow and interpretive guide for our analysis framework, and show what can
be inferred about probability distributions for $Q$, the EFT breakdown scale
$\Lambda_b$, the scale associated with soft physics in the $\chi$EFT potential
$m_{\rm eff}$, and the GP hyperparameters. All our results can be reproduced
using a publicly available Jupyter notebook, which can be straightforwardly
modified to analyze other $\chi$EFT NN potentials.
