Chewing my way through the heirloom upgrade tokens that can be purchased for Timewarped Badges at the Legion Timewalking Week vendor over at Legion’s Dalaran, and the shield and off-hand items I have in my heirloom pane don’t respond anymore to either of the two upgrade token types. So those two heirloom pieces are stuck at a lower level cap now.
I’ve seen a similar issue, what level is the character you are using to upgrade using the tokens?
Similar issue was that players could not upgrade on a max level, but when they used a lower level character (<40 perhaps) they could upgrade the gear.
If you have any level lower characters, try mailing the upgrade tokens to them and have them apply it to the heirlooms, see if that works.
Look at that, it worked! I have a plethora of alts, a few of which are specifically level 60, and I could send one of them to buy the requisite upgrade tokens that bring the heirloom item from 50 cap to 60 cap and make them work.
Fair to mention, it does mean that the final upgrade token can’t be purchased at all on that character, since the ones bought with TW badges require the character to be level 70 to buy them at all.
Glad it worked.It’s not a fix and I still consider this to be a bug but at least there is a workaround.