Appear a line of bump under the glass

My new apple watch series 6 44mm appears a line of bump under the glass and screen panel is not flat in orther positions. It can be seen clearly under the light at an angle. I sent it back to Apple Authorized Reseller, where I bought it (FPT Shop in Viet Nam) to check warranty. After 8days, they responsed to me: “it is not defect”. I dont satisfy with this result. Is my issue normal? And this issue appears on almost your apple watch?