Omuamua was accelerating as it left the solar system. How weird is that? So it actually wasn’t weird to think it might be a spacecraft.
"Observations show that the expansion of the universe is accelerating, such that the velocity at which a distant galaxy recedes from the observer is continuously increasing with time. The accelerated expansion was discovered during 1998, by two independent projects, the Supernova Cosmology Project and the High-Z Supernova Search Team"
"Every day, it's a-getting faster
Everyone said, "Go ahead and ask her"
Love like yours will surely come my way
A-hey, a-hey-hey" ~Buddy Holly 1957