padarray inconsistent behavior for n=1 axes

I found the following surprising.

n = 0
x = rand(50,100);
xr = repeat(x,outer=[1 1 n])
println(size(xr))
pxr = ImageFiltering.padarray(xr,ImageFiltering.Pad(:reflect,(5,5,0)));
println(size(pxr))

For n!=1 this succeeds and pads the repeated matrix which is of dimension (50,100,n) to be (60,110,n). For n=1, this fails with the following error message.

"DimensionMismatch: supplied axes do not agree with the size of the array (got size (1,) for the array and (0,) for the indices"

Maybe there is something I am not understanding, but I would have expected the n=1 case to behave similarly.

Reproduce the issue from the supplied Julia example, comparing ImageFiltering.padarray for n=0, n=1, and another non-1 value with the reflected padding arguments. Trace the padarray entry point and the dimension or axes handling involved; done means the n=1 case produces the expected padded size without the DimensionMismatch.