I’m fairly certain it’s a {brms} related issue. When running using {cmdstanr} with raw Stan code, there are no warnings or messages (beyond a duplicate -rpath warning related to this Warning of duplicate -rpath when compiling and installing CmdStan) :
file <- file.path(cmdstan_path(), "examples", "bernoulli", "bernoulli.stan")
mod <- cmdstan_model(file)
#> Compiling Stan program...
#> ld: warning: duplicate -rpath '/Users/andrew/.cmdstan/cmdstan-2.33.1/stan/lib/stan_math/lib/tbb' ignored
This post here ( Diagnosing machine-specific sampling problem (brms, cmdstanr)) seems to have a similar (identical?) issue—I haven’t tried any more complex models yet to see if things sample.
This post by @bbolker seems to be the same/similar issue too Informational messages (normal_id_glm_lpdf: Scale vector is inf, but must be positive finite)