https://www.recode.net/2018/2/23/17046120/instacart-tips-bug-waive-service-fee >Instacart’s tumultuous relationship with the workforce that picks and delivers groceries to the company’s customers just took another hit. >The $4 billion grocery-delivery startup admitted in a blog post on Friday that it had mistakenly withheld tips from some of its workforce, and failed to waive service fees in some instances when its customers requested to.