I have "hide read posts" enabled on the Lemmy side, through the desktop page.
When I go to my profile on Lemmy's website, I don't see any posts I've made (which makes sense, I've read every post I've ever written), but I do see all my comments in the comment section of a read post.
For some reason, on Sync it doesn't show the posts or the comments. My profile is completely empty unless I go into the settings on my Lemmy instance and toggle the "hide read" setting.