What these persistent issues represent are prior versions of OC where the master branch on Github has remained on an resolved state, which means similar or identical events that are reflected and can be reproduced since prior releases. This is what the terminologies of: persistent issues means.
The most generated errors being found on Opencart forum originates from contributed programming. The increased post counters are caused by redundancies of the same solutions that were already provided prior.
Programmer / Opencart Tester