How is collab_matrix() defined? I think the columns are all pointing to the same array, which happens if you do something like this:
julia> using DataFrames
julia> a = [0, 0, 0];
julia> dx = DataFrame(AD = a, AE = a);
julia> dx[1, 1] = 1;
julia> dx
3×2 DataFrame
│ Row │ AD │ AE │
│ │ Int64 │ Int64 │
├─────┼───────┼───────┤
│ 1 │ 1 │ 1 │
│ 2 │ 0 │ 0 │
│ 3 │ 0 │ 0 │