The point of view occasionally slips; characters swing in and out of the action seemingly without reason.
You were wearing gloves, but your hand slipped occasionally.
The book slips occasionally into hackneyed territory, especially in its later stages.
Ordinary people can occasionally slip into Tel'aran'rhiod, and events that occur within this dream world have physical consequences.
But still a blissfully surreal phrase will occasionally slip through.
How do you feel about writers who occasionally slip an unfamiliar word into their prose?
Sojan did the same, the beast slipped occasionally and nearly slid back but eventually it reached the top.
Small numbers of refugees occasionally slip into the camp to this day.
Ms. Gohl knows that things occasionally slip through the fingers of even the best detectives.
Even with precautionary measures in place, businesses that accept checks may still have a bad check occasionally slip by.