EDIT 2 (10:00 AM UTC):
Thank you for your patience while we have investigated this issue. Unfortunately we are unable to separate the Omega and Masquerade Quest Icons that are currently overlapping. However, we have extended the Masquerade Quest by 12 hours, to give players enough time to complete it once it is visible.
We would again like to express our sincere apologies for this issue. We have sent a small gift to all players’ in-game Inbox.
EDIT: Some players have been able to access the Masquerade Quest by carefully tapping on the right edge of the Quest Icon. This is a temporary solution while we work towards making the quest visible again.
There is currently a known issue with the Masquerade Quest not being visible in the Quest View. We are investigating the issue and trying to get it resolved as soon as possible.
Our apologies for the inconvenience. We will post any updates to this issue here.