@letmein3-0 Fix 1: Quick Preset Refresh (Fastest Workaround)Click the Easy Setup button in the top-right corner of Opera (the sliders icon). Change the Theme/Preset to another option. Change it back to your original choice.The link hover box should work again.
Fix 2: Change Startup SettingsOpen settings by typing opera://settings in the address bar. Scroll to On startup.Choose "Retain tabs from previous session" instead of "Begin with a fresh start page". (The default start page can trigger this bug).
Fix 3: Restart Opera Completely. Close all Opera windows. Open Task Manager (Press Ctrl + Shift + Esc). Find Opera in the list, right-click it, and pick End Task.Open Opera again.