Maintenance for the week of November 18:
• PC/Mac: No maintenance – November 18
• ESO Store and Account System for maintenance – November 19, 9:00AM EST (14:00 UTC) - 6:00PM EST (23:00 UTC)
• PlayStation®: EU megaserver for maintenance – November 19, 23:00 UTC (6:00PM EST) - November 20, 17:00 UTC (12:00PM EST) https://forums.elderscrollsonline.com/en/discussion/668861
I wonder if there is something in Tuesday's patch which they need to assess before making a final decision to enable or cancel the event this week. Typically the event pages on the website go up a week ahead of time, so it is strange for them to be cutting it close this time.
My guess: MYM will have new pokemon for us to collect and ZOS needs to tell us what it is, but they wanted to talk about it during chapter announcement so we'll be waiting till tomorrows night (or whatever it will happen to be in your time zone)