Bug? Highlight Unread comment not working on iPhone

Dear wpdiscuz Team!

I am experiencing truble to see the highlighted unread comments on iOS(12 and 11 tested), though it works on Android at least on the p20 pro where I tested, and Desktop.

Could you please fix it?

Oh and one more thing, last time I updated the plugin, all my css and settings were lost. Is this normal?

Thank you!