Shimano's misfire?
 

Just received a new CS-HG500-10s 12-28 cassette and it appears to have no spacer between 14 and the [15-28] block. From my 3 previous experiences with the HG500 cassettes, higher gears past the main block are all one-piece metal gears that integrate the spacer by design (unlike, say, Ultegra, that has separate 2.35mm plastic spacers between each gear). Was the 14t supposed to have the spacer in its design, or was the box supposed to include a single plastic spacer? Interesting.... Has anyone experienced something similar?

https://cimg3.ibsrv.net/gimg/bikefor...054a39cc4d.jpg
https://cimg4.ibsrv.net/gimg/bikefor...3e19ec6f13.jpg

Someone has fitted the cassette and then changed their mind and put the cassette back and forgotten the spacer.

So we are 100% sure that the spacer has not been slipped in elsewhere?

100% sure haha

Can you just use a spacer from your old cassette?

That would be cool, but the two cassettes that aren't in use are 11-34, which don't have a removable spacer. I found one on Ebay (from the same seller) and am waiting on the response. We shall see :)

I had a sort of similar thing with a Shimano cassette years ago where there were two cogs of the same tooth number and missing the correct cog. The shop I bought it from notified Shimano and they wanted it back in a big way. They ended up giving me two new cassettes which I never asked for. Great service from the shop and Shimano. Not sure if your seller is an official Shimano dealer and if it would make a difference when trying to get it corrected. Hopefully the seller will make it right.

I have not had the issue buying genuine Shimano cassettes new in box from an authorized reseller. Ebay and places like that usually aren't authorized resellers if they are that shouldn't have happened and if they aren't let's just hope they will help you and hope they are selling actual real Shimano product or you can get your money back and get real Shimano product.

Luckily, this is a great shop (I've purchased about 5 items from them in the last month) and they're sending me a spacer asap!