Vector `setindex!!` on arrays of arrays fails

[penelopeysm]

julia> x = fill(1, 2, 2)
2×2 Matrix{Int64}:
 1  1
 1  1

julia> BangBang.setindex!!(x, ["a", "a"], 1, :)
2×2 Matrix{Any}:
  "a"   "a"
 1     1

julia> y = fill([1], 2, 2)
2×2 Matrix{Vector{Int64}}:
 [1]  [1]
 [1]  [1]

julia> BangBang.setindex!!(y, ["a", "a"], 1, :)
ERROR: MethodError: Cannot `convert` an object of type
  String to an object of type
  Vector

Stacktrace:
  [1] setindex!
    @ ./array.jl:994 [inlined]
  [2] macro expansion
    @ ./multidimensional.jl:981 [inlined]
  [3] macro expansion
    @ ./cartesian.jl:64 [inlined]
  [4] _unsafe_setindex!
    @ ./multidimensional.jl:979 [inlined]
  [5] _setindex!
    @ ./multidimensional.jl:967 [inlined]
  [6] setindex!
    @ ./abstractarray.jl:1413 [inlined]
  [7] _setindex(::Matrix{Vector{Int64}}, ::Vector{String}, ::Int64, ::Function)
    @ BangBang.NoBang ~/.julia/packages/BangBang/9Z60G/src/NoBang/base.jl:135
  [8] may
    @ ~/.julia/packages/BangBang/9Z60G/src/core.jl:11 [inlined]
  [9] setindex!!(::Matrix{Vector{Int64}}, ::Vector{String}, ::Int64, ::Function)
    @ BangBang ~/.julia/packages/BangBang/9Z60G/src/base.jl:478

One would probably expect to get

2×2 Matrix{Any}:
 "a"  "a"
 [1]  [1]