Region allocator strage error

[ref2401 via Digitalmars-d-learn]

I am getting runtime error: 
core.exception.AssertError@std\experimental\allocator\building_blocks\region.d(235): Assertion failure

if LEN equals to 3, 5, 7, 9, ...
void main(string[] args) {
        ubyte[1024] memory;
        auto stackAlloc = Region!NullAllocator(memory);
        IAllocator alloc = allocatorObject(&stackAlloc);

        enum LEN = 11;
        float[] arr = alloc.makeArray!float(LEN);
        alloc.expandArray(arr, LEN);
}

OS: win 8.1 Enterprise x64
DMD: 2070.0
platformAlignment: 8

Any thoughts?
Thank you.