The situation:
My chatflows used the In Memory Vector Store and everything was fine until I pulled the latest Flowise docker image, after which the vector store just stopped working. The issue was closed in May 2024. A maintainer responded on the thread and the reporter confirmed it was fixed.
What actually fixes it (verified in the thread):
This was a regression in the Flowise docker build that broke the In Memory Vector Store. The maintainer pushed the fix in release 1.8.1, so the answer is to upgrade to 1.8.1 or later and pull the new image. The reporter thanked them and confirmed it worked, so theres no config workaround, just the version.