Does hydrolysis of an ester still occur in deionized or distilled water?

Yes, but only in very small amounts. Hydrolysis of an ester is catalyzed by hydronium ions in acidic solutions, so the reaction occurs at a measurable rate. But even in neutral solution, there will be a very slow hydrolysis. And as the hydrolysis proceeds, it will produce some acid, which will then start to speed the reaction as the solution gets more acidic.