My best guess is that you abandoned the profile you had these emblems on when you enabled cross save. Unless you manually linked your profiles together on a singular Bungie profile, you likely had a Bungie profile for each platform account you used (one for PSN and one for Battle.net/Steam). When you redeemed the codes for the emblems, they were bound to the Bungie profile that you logged in with. When you enabled cross save, you linked all your platform accounts under one Bungie profile. The profile that was linked to the account you imported in became orphaned, and with it any emblems you had redeemed onto it. It may be possible for you reclaim the original profile, but it will require you to break cross save, unlink the account you imported (probably your Battle.net one), log out of Bungie and then log back in with your Battle.net account. If it works correctly, it should link you to the original profile. You can then abandon the other profile if you choose to, and link it all onto the reclaimed profile. You will need to wait 90 days before you can enable cross save again, however.