HTML email applies style to all text after Update 10.4

After upgrading to 10.4, while applying a style to text in my HTML Email like Bold or Underline, the entire content within the table in my email has that style applied, instead of the specific text selected/highlighted. I’ve tried everything, but this issue persists specifically if the Email is HTML-based, and has been prevalent since exactly after the upgrade.

Any suggestions/recommendations are welcome.