I don’t think the pill can really lose its magnetism unless it was done intentionally. I would guess that maybe something got disconnected when you cleaned the cuvette. I would open it back up and check the connections.
There was a Lab where I worked, and I know they replaced the magnetic bars, that went into the solutions, fairly often. If you don’t use a “Keeper,” on a magnet, they don’t last as long. Also dropping and hard bumps will decrease magnetism.
I used a knife to remove the pill and it stuck to it. As far as bumps go, it has been well taken care of. I think it just “quit” working for some reason. Maybe an electric spike or whatever, don’t know. Just hate tip send it to Neptune for them to replace something that is so easy to repair if I had the part…