I think I fixed it myself but would like someone from Twitch to verify - basically in line 98 of api.ts in https://github.com/twitchdev/developer-rig/blob/master/src/util/api.ts I commented out the “&& response.products.length” so it doesn’t throw an error when there is 0 products, it seems to work ok now…but would like a confirm. 
Edit: Looking at the source history - looks like its a legit bug!