This solution worked for me unfortunately
After doing various steps (delete cache, restart phone, uninstall reinstall, boot mode clear system cache) the only solution unfortunately, I found was to do factory reset for my wife Samsung s7 edge oreo and setup as new phone (restoring via backup will bring you back to square 1). After that all is well and no more problems. It worked for me and hope it works for others out there. (happy wife now phew) Probably the last ultimatum. Make sure to do your due diligence!