This is due to a misunderstanding of how categories and parent terms work.
To demonstrate the point, consider:
Forestry machinery > chainsaws > 12″ Chainsaw bars.
If I add a product to 12″ chainsaw bars, is it:
- a 12″ chainsaw bar
- a chainsaw
- forestry machinery
The answer to all 3 is yes. Parent terms aren’t just a way to organise terms. Child terms are contained by them.
So rather than thinking of them as connected boxes, think of them as nested boxes. A term includes all of its children, so by putting a product in the 12" chainsaw bar category, you’re indicating it is also a member of the more general chainsaw category, which is also a member of the more general forestry machinery category.
SECONDLY. My main slug categories duplicate on the HOME page.
We have a 1 question per question policy, your second question should be asked as a second question. Include the code that generates that section or it will be impossible to answer. Also HTTP 500 errors, are just the servers way of saying “Something went wrong in PHP, don’t know what it was, check the error log for the actual problem”, you will need that error message