R fatal error when calling pairs

Summary:

Calling pairs() on two different models has resulted in 2 R fatal errors/R sessions aborted.

Description:

I created the models with brm() in the BRMS package. I received warnings that there were many (~200) divergent transitions with the first model that crashed and just 1 divergent transition the second time it crashed. I have successfully run the pairs() function once but there were no red dots in it which I expected based on my reading of what the pairs() function does. The other time I managed to get a plot, the plot was broken.

Reproducible Steps:

Here is the data I used:
SampleData.xlsx

And the code I used for the second time it crashed:

prior<-get_prior(formula = bf(value ~ 1 + allowed_vote + (1|Participant) + (1|variable))+
    lf(disc ~ 0 + allowed_vote, cmc = FALSE),
  data = data,
  family = acat("probit"))

fit_G3_withPriors<-brm(
  formula = bf(value ~ 1 + allowed_vote + (1|Participant) + (1|variable))+
    lf(disc ~ 0 + allowed_vote, cmc = FALSE),
  data = data,
  family = cumulative("probit"),
  save_all_pars = TRUE,
  prior = prior
)

pairs(fit_G3_withPriors)

Current Output:

The message when crashing with a cumulative model with unequal variances:

The plot I got that was clearly broken (from running adjacent category model with category-specific effects):

The plot I got when pairs() actually ran with a cumulative model with equal variances:

Expected Output:

The pairs plot is supposed to show divergent transitions with red points but even when pairs ran, I don't see any red points in the pairs() plot (though I believe in that case there was only one divergent transition).

Versions:

rstan_2.21.2
brms_2.13.5
R version 4.0.2

Start by reproducing pairs(fit_G3_withPriors) from the supplied R code and SampleData.xlsx with the listed rstan, brms, and R versions. Inspect the pairs plotting path for the cumulative and adjacent-category models, then verify that the session no longer aborts and that divergent transitions are represented correctly in the resulting plot.