I don't understand why this is suspicious? There is in principle a vast parameter space to cover (in particular as the dark matter mass can be anything), and only a fraction of it is covered. Therefore, even if we have three ways to look for dark matter and that these three ways are complementary, we are by far not sensitive to all possibilities.
As a consequence, the no-signal result is not that negative.
If you can see the event, it's not a dark matter event!
I can smell it.... I am COVID-negative ;)