no one knows for sure about the end of the Oikos project, but judging from the activity of the bounty and the Oikos project site is not a scam, you don't need to panic if there is an additional duration of time because there are many bounty projects like that.
There was no indication from oikos to be a scam project. The team has the right to extend the campaign as long as they were adding more reward to the participants.
Investors are still also actively asking the developer in telegram group too.
Maybe the OP was too panicked to draw conclusions like this that made many people believe that Oikos was still going on with the bounty at this time, the duration of the extension was normal at the bounty meaning the Oikos project wanted to continue promoting it.