Calling pmap from thread hangs

New to Julia
1

Hi, for some reason the code snippet below hangs. Does any one have an explanation as to why this hangs

using distributed
addprocs(2)
tasks = Vector{Task}(undef,4)
@sync for i in 1:4
       tasks[i] = Threads.@spawn begin
           pmap(x->x, WorkerPool(workers()), 1:10)
       end
end
fetch.(tasks)

Surprisingly if i first run pmap(x->x, WorkerPool(workers()), 1:10) before running the code above everything works as expected.