Game bugs
It must have been a system bug.
Usually a few days before the month expires I don't collect the "Weekly Contracts" and then collect them on the first of the following month before they expire.
Now it happened that after midnight on March 31st and that is April 1st when I entered the game the "War Pass" was already at April 1st and I collected the "Weekly Contracts" rewards reaching "5 points" of "War Pass" level. Ok! Now at 15:00 on April 1st I go back to the game and see that everything has reset. The "Weekly Contracts" are no longer there and the "War Pass" level has returned to "1".