We are aware of the issues players are seeing with upgrading the Bayrak using tokens. When tokens are being used for the 20+ levels there is a red box error and the tokens are not upgrading as they should.
Hold off on using Bayrak Upgrade Tokens until after the downtime.
The team is currently working on a fix, but this will require downtime at 10:30am PDT (1:30pm EST, 7:30 CET) . The Holdout event start time has been pushed to 12pm PDT (3pm EST, 9pm CET). The end time and store are adjusted as well so you will not lose any time to earn XP and claim prizes.