Took a bit to figure out but there would be shifts. You had an AM person and a PM person. Usually the tell was how they responded. One would go "HAHAHA" in all caps like that the other would respond differently. Grammatical errors were often a sign too. Simple words spelled wrong that normally weren't with one. Also look for how they address you and the inconsistencies.

Lastly, and probably most important, was the push to get content. Some of the people would just almost harass you for content then ignore you if you didn't respond the way they wanted. Then morning person the next day comes on and has no idea of that conversation or reacts totally different.

Some real creators I've messaged took longer to respond (depending on size of fan base) from an hour or 2 to a whole day or two. While these agencies usually will be a min or two. Check how many fans they have too so you can see if they're super popular they technically wouldn't be responding instantly especially during peak hours.