Is there a way to fix this issue?
If you think it's a session issue, you can close Opera and delete the "Sessions" folder in the profile folder to start with a fresh session. You'll lose all your tabs though, but that might fix it.
If you want to save your tabs, right-click on a tab, goto "save" and choose "all tabs to a speed dial folder". Then, with the new session, right-click that folder and choose "open all in tabs". You'd have to do that for each workspace too if you're using more than the default one.