It's not just the use of @gmail.com, it's the fact that it's clearly an autogenerated address with random chars that tripped me. If it was claiming to be a sma

It's not just the use of @gmail.com, it's the fact that it's clearly an autogenerated address with random chars that tripped me. If it was claiming to be a small business from companyname@gmail.com, I'd be less suspicious - but a large corporate not using their own domain for mail, the email address itself, and the then switching to a second email address are all giant red flags for me.