The phrase "occasional moments" refers to certain times or instances that happen once in a while. It means that something occurs only from time to time, not regularly or frequently. Full definition
That said, there have been more varied groups of children collected in many other films, and in spite of occasional moments of empathy or humour, they fail to capture the imagination. (hoopla.nu)
There are occasional moments when a character makes a mistake and you'll probably scream at the TV. (ps3attitude.com)
It's a mostly gentle movie with occasional moments of truth. (rogerebert.com)