After about 1 week of updating the site and 1 week of also not touching the site, the custom post types that disappeared before has stayed. Thank you Michael, you were correct about the positioning fields, not using them was the culprit for the original disappearances!
My team and I updated and worked on the wodpress site throughout the week, so it was being monitored. Will update in about a week or two to report if they disappear again! Hopefully not setting positions will be the culprit!
The first couple of times, I did position each of the post types using the menu position field. I did recreate them again, but this time didn’t position them, they are on the dashboard menu, but the last couple of times they disappeared, it was after about a week. Perhaps, they will stay this time since the other post types that didn’t disappear wasn’t positioned!
