Is there anything worse than being all psyched up for a big in-game event, only to find out at the last minute that the event will not be running as planned? Yes. There are many things worse. But that’s still the reality that Warframe players had to deal with when Operation: Plague Star did not launch as planned; unfortunately, the delay of the event was due to what sounds like a pretty serious bug that rendered the operation outright impossible to complete.
This in and of itself would be problem enough, but it also contained a bug causing the game to crash on its Xbox version, requiring a full check through certification once fixed. As the developers are keen on the event starting at the same time for every platform, that means waiting until the issues are fixed and the certification process is complete (which should be quick, thankfully). So fans will hopefully will need only wait a little while longer, but they will need to wait, just the same.
"Where is Operation: Plague Star?"
A bit more time is needed to address Plague Star issues before we ship it. We're doing our best to make this happen as quickly as possible for you!
Full information here: https://t.co/xzuqSBuuiS
— Megan Everett (@moitoi) June 12, 2019
Source: Official Forums