what you’re describing sounds like some sort of throttling, but i can’t trigger any throttling on that autocomplete box myself. you’ve described in the past another situation that sounded like throttling (https://forum.inaturalist.org/t/slow-website-loading/12174/14) that i also could not reproduce. so i’m thinking there’s something on your end – maybe your setup or maybe the process that you’re using to load your observations – that is causing these problems.
unfortunately, if no one can reproduce the problem reliably, then it will be really hard to help you, i suspect. if you can provide screenshots of your browser console messages and browser network activity, i think that could provide more clues.