I think this whole behaviour could be cancelled out by making auto-renew instant. So the moment the money comes back to the lender, the offer to lend is renewed. Since the creation of the new offer is automatic and only conditioned on a single flag (whether auto-renew is still on) this should be a very lean and fast operation CPU wise for Bitfinex.

Now with this in place if you take all offers and cancel them, the offers will just immediately reappear, and you lost 1 hour of interest money for nothing.

It's like auto-renew but instant and without this apparently expensive timer batch job.