The user @kanczo suggested something in another related topic that worked for him and is now working for me as well. The 'fix' is outlined below:
"When your phone is on the 'Follow the instructions on the other device' screen, simply press the 'Overview' (app-switching) button and force-close Opera. When you relaunch Opera on your phone, the flow should already be connected."
I hope this works for all of you while Opera doesn't directly address this issue.
Thanks, @kanczo, for coming back and sharing your solution with us!