"Ce matin-là, j'ai rencontré Julie dans le bus."

Translation: That morning, I met Julie on the bus.

[MohamadIta13]

That morning I came across Julie on the bus. Marked wrong as well!!

[GraemeSarg]

I think that "came across" and "ran into" would both be better as: "Ce matin-là, j'ai croisé Julie dans le bus.".

But croiser, rencontrer and tomber sur are synonymous in this context and both should be accepted here.