For some people in the world of academic science, it is a big deal to "get scooped".
What does this mean?
It is generally when someone publishes a paper that reports a finding that is identical, or similar, to the work you hope to publish.
Publishing first, for many of us, has important beneficial implications. It can mean the difference in which journal will publish your work. The ones higher on the journal totem pole will be least likely to publish your work if it is similar to something that has already been published. They all will sneer, at least a little, at direct replications.
This can be as ridiculous as a 2 week difference in submission date for two papers that obviously took many years worth of effort to produce, btw.
It can be the deciding factor for who gets the lasting credit for a given discovery or demonstration, garning preferential citations, approval and appreciation.
In some cases, due to the preferences of the collaborators or the supervising PI this can be the difference in publishing your work at all. "If we can't publish in Nature or Science, then we won't publish at all!" goes the thinking in some quarters. (I know, I know..... if you aren't as familiar with this it seems idiotic. It is. I know. But it still exists. Replication? That's for the little people.)
Getting scooped is the easier* determination.
The harder question is deciding if someone intentionally scooped you.
I'm here to tell you that the accusations of intentional scooping run far in advance of the actual existence of it. But, it does exist. Of course. People can certainly choose what to work on based on knowledge of what you are doing. They can alter their allocation of resources to a project based on knowledge of how close you are to publishing. They can rush a manuscript to a journal earlier than they might have otherwise done based on knowing your timeline. And, of course, they can intentionally slow your progress if they happen to get your manuscript to review by delaying submitting their reviews, by demanding additional experimentation and by recommending rejection from a particular journal .
It is possible.
But it does not seem to me to be possible that this is the case for all of the accusations I hear from people that another lab intentionally scooped, or tried to scoop, their project.
*Not "easy" because it isn't cut and dried what reflects an actual scoop. Many different pieces in your average research article these days. Unlikely that two groups come up with precisely identical manuscripts.