We've been having some Sales Orders coming through SuiteCommerce with 0 quantity lines - as in, they'll have 2 of Item A, 2 of Item B, but then also a line for 0 of Item A. We have been unable to replicate the issue in sandbox, and have turned off the cart customizations we have in PROD for the time being, but it seems they still come through randomly. No similarities that I can find between the orders, all for different items, different customers, different terms, different payment methods, etc. Not really a big deal as the customer is not affected, but definitely a head scratcher for me. Any thoughts?

Do you use SuiteCommerce Standard or Advanced? If Advanced, which version? I struggle with the same issue on version 2019.1, never figured it out. But it might be a scriptable cart or a custom module/core that is using the Commerce API, the extensibility does not allow you to set/update an item without a quantity > 0.

I'm on SuiteCommerce Standard currently

I'll receive rare bug reports of this happening on SCA Kilimanjaro. Like maybe once a year, rare. No idea.

I tried to reproduce this and I wasn't able to. There are a lot of checks to prevent 0 quantity line items in SC/A. It is possible, AFAIK, to do it in the NetSuite UI but I can't see how it is possible in the commerce app. So yeah, if you ever figure out steps to replicate, would love to see them.