It's random at best, no telling when it's coming, though the ship tends to shake and the Admiral will announce that we're taking on water. To a collective groan from the general populace. At least this wasn't...terrible.

[She makes a face.]

Essentially, yeah. I just usually go with Barge magic. Easier to deal with than the actual scientific theory and mechanics. I get enough temporal fuck up from time-travel and all of its implications.