I have looked harder at the this.
To have 5 mm of play between the part 6015 spacer and the swing arm, either the spindle does not fit the swingarm slot properly, it should engage on two flats, or ,either spacer 6015 or spindle 6014 is the wrong part, could be either, could be both.
This is dangerous, if spacer 6015 is free to move then the bearing centre is not trapped corectly
the sprocket assembly should be locked solid to the swing arm with no play at all , spacer 6015 should push on the inner bearing ring, the sprocket should spin freely .
Spindle 6014 has 3 steps, the largest diameter locates against the dust seal and bearing inner ring
the second step should be the fit of the bearing depth / thickness
spacer 6015 should fit on the third step with the large side to the bearing and be locked in place when its assembled with the spindle nut tight.
the third step is where the 2 flats locate on the swing arm slot, then threads to take the nut
Either the third step of the spindle 6014 is too long or incorrect in other ways , or spacer 6015 is too short .
Maybe it can be made to work with additional spacers, beware , check sprocket alignment, this may be affected , as may the centre line of the back wheel.
I found a PDF on line showing the rear sprocket and spindle bearing repair, page F6 fig 8 in the Work Shop manual
shows the spacer 6015 with the large end, AND a smaller spacer the same OD as the thin end of 6015, this is not shown on the dragnfly info or in the WSM text. This was on a private members site so I cant link it , sorry. Could be the answer one unnamed no part number piece that just exists as a piece of forgotten artwork.