I have a partial workaround! I started downgrading packages and arrived at this configuration that works:
(@v1.5) pkg> status CSV DataFrames PooledArrays CategoricalArrays
Status `~/.julia/environments/v1.5/Project.toml`
[336ed68f] CSV v0.8.2
[324d7699] CategoricalArrays v0.9.0
[a93c6f00] DataFrames v0.22.3
[2dfb63ee] PooledArrays v0.5.3
(@v1.5) pkg>
I’m not sure exactly where the issue is, and it might be in just one or two of these packages. I’ll try to keep narrowing it down from here. I got to this state with
(@v1.5) pkg> rm CSV
(@v1.5) pkg> rm DataFrames
(@v1.5) pkg> rm PooledArrays
(@v1.5) pkg> rm CategoricalArrays
(@v1.5) pkg> add CSV@0.8.2
(@v1.5) pkg> add CategoricalArrays@0.9.0
(@v1.5) pkg> add DataFrames@0.22.3
(@v1.5) pkg> add PooledArrays@0.5.3
Hope this helps!