For many players(casual ones) the event was on the limit and to their surprise and mine too, they finished in the Silver league, got the golden upgrade but to their surprise they lack a normal upgrade. They have 2 bases, 7 upgrades and 1 golden upgrade, so they ended up short of 1 normal upgrade and can't have the building at maximum level. It just shows how unbalanced the event was: finish in the top 5% and not being able to complete the building.
A real mess from Inno, bugged event and with one extra day lots of players couldn't finish the building.
I was somehow lucky to have the building completed on all of my secondary worlds, I went for the league, I didn't even count the normal upgrades, I couldn't imagine the scenario of being able to get the golden upgrade but not enough normal upgrades. Luckily enough I learned well how to play the candy crush mini game, how to plan, when to use the coins, but a casual player just plays the game relaxed without too many worries and sometimes he even misses few tickets by not using all his free tickets on time. Many events like this one or St. Patrick have become something that only experienced / elite and 100% focused players can finish for free.