Display error? IBTD!
It's more like a wrong label, a promotion not granted.
As a fact, the affected players still sit at the displayed lower level, and none of the equipment in the next level is available to them.
Once in a while? IBTD!
There have been at least three reports in a few days, and they all concern players of levels >90, with severe XP spaces between the tiers.
In this case here, lvl 96 will be at 1,291,355 XPs, roughly 193,000 XPs to go. This equates to a few months, an unconvenient situation for your client.
Earlier this year, you have pointed to CS in multiple cases with the promise of help. Is this still an option, if not, why has it been withdrawn?