Source of mystery history checkpoint after Android swipe typing?

When swipe-typing on Android, even if you set newGroupDelay to Math.POSITIVE_INFINITY, inserting text via swipe-typing still creates history checkpoints.

What is the source of these? Can they be disabled?

We’d like to handle history in a more deliberate fashion but if we do so then we end up with twice as many history checkpoints as expected when the user swipe-types.