mapslices on a Dataset returns a wrong cube

Running mapslices on a Dataset should return another Dataset, instead it returns an odd cube:

using YAXArrays

a = YAXArray(ones(10,10,10))
b = YAXArray(ones(10,10,10))
c = YAXArray(ones(10,10,10))

axes = Dict(:Dim_1 => a.axes[1], :Dim_2 => a.axes[2], :Dim_3 => a.axes[3])

dataset = Dataset(Dict(:a => a, :b => b, :c => c), test_axes, Dict("test" => "test"))

slice = mapslices(mean, dataset; dims="Dim_1")

println(slice)

I expect a dataset to be returned with the correct variables, instead I get this cube:

YAXArray with the following dimensions
OutAxis1            Axis with 10 Elements from 1 to 10
Dim_2               Axis with 10 Elements from 1 to 10
Dim_3               Axis with 10 Elements from 1 to 10
Total size: 7.81 KB

In addition to the following warning:

[ Info: Found multiple matching axes for output dimension 1

Start by reproducing the mapslices(mean, dataset; dims="Dim_1") example from the issue and inspect the Dataset and mapslices entry points involved. The fix is complete when the operation returns a Dataset with the expected variables and dimensions without the multiple-matching-axes warning.