On several of our posts, we try to add/change tags, and they don't get saved correctly. They keep defaulting to a set of tags that have nothing to do with the article. For example, the tag "lead", "toilet" or "plumber" will appear after we have saved correct tags on those posts that have nothing to do with lead or toilet.
In this article on hardwood floors, I have changed the tags many times and saved them. Yet the only tag available for it is "lead".
On this article on repairing leaky roofs, the only tag is toilet.
There are more as well.
Why is this happening on these specific articles and how can I prevent it happening to future posts?