Engineering culture is abrasive. Disagreements are natural, but there is a concerning amount of bad-mouthing behind people's backs about technological decisions. There is definitely some unhealthy competition within teams as well as cross-team.
I would not say that it is close to Uber levels of bad, but as the company scales at the rate that it has it will MOST DEFINITELY get out of hand. The negatively is contagious and its spread has been visible for some time.
Transparency has also gone down significantly since the acquisition and it's unclear what Walmart leadership has planned for certain divisions.