You add memory to your agent with Mem0, ship it, and it works great in your dev environment where you're the only user. Then you go multi-tenant — real users, real sessions — and three weeks later someone reports that the agent "remembers" something they never told it. It's not a hallucination. It's another user's memory, served straight from your own vector store.
This is the single most common Mem0 integration bug I run into, and the fix is one filter you're probably not passing consistently. Here's the 15-minute version.
The setup that causes it
Most Mem0 quickstarts look like this:
from mem0 import Memory
