The +/- buttons ignore my step
Your theme ships its own stepper. Turn on Replace theme stepper in Settings → Quantity & Pricing → General.
The hint or stepper is missing on a custom page
Page builders and landing pages are not always detected. Turn on Load assets everywhere under Advanced.
A quantity got into the cart that breaks the rule
Was the rule tightened after the item was added? Cart items are re-validated on the cart and checkout pages, and the block cart snaps them to the nearest valid value automatically.
Another plugin may filter quantities later than we do. Raise the plugin’s Hook priorities under Advanced.
Rules are not applied to some products
Check the Quantity & Pricing tab on that product: a product rule with 0 in a field means “no limit” and overrides the store default. Blank means inherit.
Conflicts with another min/max plugin
Run one quantity plugin at a time. If both are active the later one wins and messages become inconsistent.
Still stuck?
Free users: WordPress.org support forum. Pro users: contact us. Include WooCommerce → Status → System report.