It might be possible the content is copied from somewhere and while pasting it took the formatting of the source text.
Can you reauthor your text in rte after removing the source formatting?[You can use various method to remove formatting like an online tool https://www.textcleanr.com/# or copy the text in word and remove formatting before pasting it in richtext]
@SreekanthReddy How did you author your RTE ? The content which I can see via inspect element doesn't look like authored via RTE field. It can be possible it might be source edited ? Could you please confirm how this is authored ? If you think the authoring is done properly and still it is getting added, as an additional step of debugging , can you author a page in we-retail using the same RTE component and check if the additional styles are getting added ?