Please double-check you're on the account you think you are
Nothing dramatic happened. I just noticed, on a quiet morning, that I had two accounts available and had genuinely lost track of which one was selected — and I would not have known until a fill appeared somewhere unexpected.
Now the first thing I look at is the account label, every session, out loud. Slightly ridiculous, completely free.
If you have paper and live side by side, this one is worth a habit rather than a policy.