Meta Keywords Missing!

So it appears most likely all my clients who had the previous AIOSEO with meta keywords attached, who regularly update the plugin as a new Version comes in, have now lost all the keywords associated. You say in V4.0.13 you’ve dealt with this, well so far with the sites I have viewed this has not been the case. I had to roll back to 3.7.1 copy and paste the keywords and then add them back in. I can’t do this for all my clients, nor should I need to. My client brought, suggesting I did not add them, in the first place! He has been working on his SEO the last week so rollback is not an option for him, without having to redo the work he has put in. What is going on?? Not impressed if I am honest.