Alien intelligence is looking probable.
It's properly another coincidence.
When dealing with observations in space, "Aliens" are and should be the absolute last explanation for a particular event. Aliens are often used as an explanation when we don't really have an explanation as of yet. Several other discoveries in space have stumped scientists and brought out the "it must be aliens" crowed, yet perfectly natural and reasonable explanations have later been found. Until we get hard core evidence, we can suspect this is a similar situation.
I don't know, therefore aliens.
Aliens should be a last resort explaination.