Error precompiling Plots.jl

I am getting a weird precompiling warning each time I’m trying to use Plots.jl:

[ Info: Precompiling Plots [91a5bcdd-55d7-5caf-9e0b-520d859cae80]
┌ Warning: The call to compilecache failed to create a usable precompiled cache file for FFMPEG [c87230d0-a227-11e9-1b43-d7ebe4e7570a]
│   exception = Required dependency libass_jll [0ac62f75-1d6f-5e53-bd7c-93b484bb37c0] failed to load from a cache file.
└ @ Base loading.jl:1132
┌ Warning: The call to compilecache failed to create a usable precompiled cache file for Plots [91a5bcdd-55d7-5caf-9e0b-520d859cae80]

I’ve tried updating, removing and reinstalling the package, running resolve, but nothing works. I still get the warnings.

Trying to run ] test Plots fails at the testing stage with:

ERROR: LoadError: InitError: UndefVarError: libwand not defined
Stacktrace:
 [1] magickgenesis
   @ ~/.julia/packages/ImageMagick/Fh2BX/src/libmagickwand.jl:21 [inlined]
 [2] __init__()
   @ ImageMagick ~/.julia/packages/ImageMagick/Fh2BX/src/libmagickwand.jl:27
 [3] _include_from_serialized(path::String, depmods::Vector{Any})
   @ Base ./loading.jl:768
 [4] _require_search_from_serialized(pkg::Base.PkgId, sourcepath::String)
   @ Base ./loading.jl:854
 [5] _require(pkg::Base.PkgId)
   @ Base ./loading.jl:1097
 [6] require(uuidkey::Base.PkgId)
   @ Base ./loading.jl:1013
 [7] require(into::Module, mod::Symbol)
   @ Base ./loading.jl:997
 [8] include(fname::String)
   @ Base.MainInclude ./client.jl:451
 [9] top-level scope
   @ none:6
during initialization of module ImageMagick

I’m using macOS 1.9, if that’s important.

Thanks for the help!