@robert Thanks for the well explained solution.
First of all, the tags were added during post creation, and everything else is original. We have never insert directly into WpForo's tables on DB's end. Hence, we were puzzled why does it behave in this manner. For the time being, we'll monitor on our end. Thanks for the help! @Chris @Robert
Also, could you share with me the solution to resolved? As we'd like to replicate the solution to other websites using wpforo's plugin as well.
Once again, Thank you. Looking forward to your response.