The biggest problem I have with this idea is that the story spun around it has a very high chance of being, you know, boring. While it's fun to think about the Foundation getting so invested in exploring some place that ultimately isn't worth exploring, the readers might not find any reason to care about the anomaly besides that. Even if you put that twist in the end — after so many people and drones sent in, Foundation somehow discovers that the other side of the portal or whatever has jack shit to do — the story would then become really anticlimactic, in my opinion. I don't like things set-up so grandly only to reach nothing.
Still, it would be fun to see a universe where things are perceived as boring. What if any subject who enters the pocket universe will be in for a very dangerous and thrilling adventure, sailing across miles of dessert, fighting against hoards of monsters, dueling with the deadliest of warriors, but when they meet an inhabitant of that world and recount those stories, the reactions they got are less than lackluster? "You killed The Giant Centipede of Zul-gil? It's good to have fun, but many people have attacked their nests and subdued the progenitor of the species that's a million years old just yesterday. You're just lucky to find a deserter".
And maybe, the subject will be so high in adventuring, that they will eventually set foot in a quest where their lives are not guaranteed. And then they die. Kinda a different take on heroic stories.
Or something like that. Up to you. Good luck.