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Those are processed automatically every 144 minutes (at the same time that enrollments are processed). Bonus units will update at that time and pending vote balance will immediately start to grow at the new rate.

Thanks. I assume that has to do with upvote power syncing, since it coincides with a single vote's recharge time.

Earn rates per unit are based on the per day votable rshares of 2 SP (with some adjustments for sustainability coverage and curation reward), so it made sense to slice the daily amount by 10 and run it on that interval.
We could slice it up however we want, but 144 minutes is an interval easily recognized and accepted by most experienced Steemians.