Sampling of situations that either happened to me or I have direct knowledge of:
Suspension for listing an authentic product, because the brand was listed slightly differently (think "acme products" vs "acme"). Took a week and two appeals to get reinstated
Suspension for changing bank account information (have heard many such cases - they flag it as fraud but instead of just putting payments on hold, they block all listings until resolved)
Suspensions claiming account is related to another account that's blocked. No information is given and seller is unaware of any other accounts it might be linked to
Suspension for inauthentic product. Even after invoices showing all products in question were provided, Amazon decides to ignore everything, steals the inventory valued in the 7 digits and keeps the money as well
Suspension for selling expired product. Turns out Amazon had found the product in their warehouse and decided to add it to sellers inventory, sell it, get complaints and then blame it on the seller. (Seriously. Ask anybody selling volume groceries on Amazon. Amazon is shockingly incompetent at tracking dates).
Product blocked due to false complaint by brand owner. Reinstated after sending an invoice proving authenticity. Repeat a few dozen times (sending the same exact invoice each time).
Plus one not directly related to performance but scummy behavior anyway: Amazon starts selling a product and all of a sudden blocks third party sellers from selling it. Sometimes I've had 5-6 figures of inventory get blocked this way. Makes it really difficult to run a business when they act capriciously.