What I did notice in your screenshot is that the Forms sub menu items are out of order. Both issues are most likely being caused by the theme or another plugin or even some old styles cached by SG. Have you tried clearing the SG cache and the browser cache?
Thanks for checking. Very strange it’s not happening to you. We noticed this morning that SG Optimizer (plugin) also causes a similar issue with Wordfence’s Admin menu icon.
But, alas, we did some homework this morning and discovered something that may help the developers of SG Optimizer and Wordfence fix the issue. Currently, waiting for their input.
Bottom Line: SG Optimizer and Wordfence use standard SVG images as their icons, not WP dashicons, custom dashicons, nor Base64 coded SVGs. This could be part of the problem since the standard SVG images - we noticed - were re-scaling themselves when other links were clicked. The WP icons and other plugins’ icons did not.
Anyway, closing this topic for now (here). Will update this post if and when we hear back from Wordfence – or – you can simply check the lastest post contained in the link provided.
Oh, and concerning your questions, yes we cleared all cache (many times over) and performed many other tests as noted in the link provided. The Forms submenu items are out of order because we’re using the plugin Admin Menu Editor (AME) to customize/personalize the order of these items. We did it for all plugins. And yes, we also deleted AME, reloaded WP 5.8, and cleared our cache to verify it wasn’t causing the issue.