Err multiplying block array with `Diagonal`

mortar(reshape([randn(2,2)], 1, 1))*I(2) fails while mortar(reshape([randn(2,2)], 1, 1))*Matrix(I(2)) does not

julia> mortar(reshape([randn(2,2)], 1, 1))*I(2)
ERROR: BoundsError: attempt to access 1-element Base.OneTo{Int64} at index [1:2]
Stacktrace:
  [1] throw_boundserror(A::Base.OneTo{Int64}, I::Tuple{UnitRange{Int64}})
    @ Base ./abstractarray.jl:734
  [2] checkbounds
    @ ./abstractarray.jl:699 [inlined]
  [3] getindex
    @ ./range.jl:988 [inlined]
  [4] getindex
    @ ~/.julia/packages/BlockArrays/L5yjb/src/blockaxis.jl:10 [inlined]
  [5] unblock
    @ ~/.julia/packages/BlockArrays/L5yjb/src/views.jl:10 [inlined]
  [6] to_indices
    @ ~/.julia/packages/BlockArrays/L5yjb/src/views.jl:29 [inlined]
  [7] to_indices
    @ ~/.julia/packages/BlockArrays/L5yjb/src/views.jl:44 [inlined]
  [8] view
    @ ./subarray.jl:178 [inlined]
  [9] _bview
    @ ~/.julia/packages/BlockArrays/L5yjb/src/blockbroadcast.jl:141 [inlined]
 [10] macro expansion
    @ ~/.julia/packages/BlockArrays/L5yjb/src/blockbroadcast.jl:171 [inlined]
 [11] _generic_blockbroadcast_copyto!(dest::BlockMatrix{…}, bc::Base.Broadcast.Broadcasted{…})
    @ BlockArrays ~/.julia/packages/BlockArrays/L5yjb/src/blockbroadcast.jl:147
 [12] copyto!
    @ BlockArrays ~/.julia/packages/BlockArrays/L5yjb/src/blockbroadcast.jl:188 [inlined]
 [13] copy(bc::Base.Broadcast.Broadcasted{BlockArrays.BlockStyle{…}, Tuple{…}, typeof(*), Tuple{…}})
    @ Base.Broadcast ./broadcast.jl:928
 [14] materialize
    @ ./broadcast.jl:903 [inlined]
 [15] copy(M::ArrayLayouts.Rmul{BlockArrays.BlockLayout{…}, ArrayLayouts.DiagonalLayout{…}, BlockMatrix{…}, Diagonal{…}})
    @ ArrayLayouts ~/.julia/packages/ArrayLayouts/824cB/src/diagonal.jl:20
 [16] copy
    @ ~/.julia/packages/ArrayLayouts/824cB/src/mul.jl:130 [inlined]
 [17] materialize
    @ ~/.julia/packages/ArrayLayouts/824cB/src/mul.jl:127 [inlined]
 [18] mul
    @ ~/.julia/packages/ArrayLayouts/824cB/src/mul.jl:128 [inlined]
 [19] *(A::BlockMatrix{Float64, Matrix{…}, Tuple{…}}, B::Diagonal{Bool, Vector{…}})
    @ ArrayLayouts ~/.julia/packages/ArrayLayouts/824cB/src/mul.jl:252
 [20] top-level scope
    @ REPL[120]:1
Some type information was truncated. Use `show(err)` to see complete types.

Reproduce the failure with mortar(reshape([randn(2,2)], 1, 1))*I(2) and compare it with Matrix(I(2)). Start with BlockArrays/src/blockbroadcast.jl and the unblock path in views.jl, then inspect the ArrayLayouts diagonal multiplication path shown in the stack trace. Done means the Diagonal multiplication no longer raises the reported BoundsError.