The update that was released on March 10 did not fully fix the consequences of incorrect values of Frontline Experience required to gain Frontline Tiers.
The amount of Frontline Experience in the progression has been corrected and is currently up-to-date. However, the Experience already earned was not re-calculated correctly.
As a result, some players played more battles in order to get Expedition Tokens, than it was noted in the regulations.
We will give 1 Expedition Token to those players who played at least one battle in Frontline on the first play day before ceasefire as compensation. (from Mar 8 23.00 UTC till Mar 9 20.00 UTC).
The additional token will allow saving efforts and time for getting reward tanks for both the ones who have not earned enough Frontline Experience for a token and the ones who reached Tier 15 at the first stage despite the incorrect progression.
The token will be credited with the start of the 2nd Frontline Stage (in order to get it, you’ll need to log in to the game client).
We apologize that the launch of Frontline did not go smoothly.
Source: EU Portal