Podgagement collects your podcast reviews several times every day, but your email notifications send according to the schedule in your podcast settings.
Thus, if you manually check a podcast app and see new reviews, then they are newer than the last time your podcast was refreshed by Podgagement, but you should have them in your account within a day.
Apple Podcasts takes about 34 hours to publish a newly submitted review. So that's why you can't see new reviews immediately, but we'll still notify you as soon as Podgagement collects the review (in accordance with your chosen notification schedule).