Hi Benjamin,
Thank you for your reply.
I tried in both Google Chrome and Microsoft Edge, both show the same issues. It was very first time I noticed when I wanted to upload plugins called Advanced Customs Field (ACF). Since, it was not searching so I manually found it and uploaded the plugins.
I have similar issues.. such as I created customs field called, Related Program(s), giving relation to another post called Events. But it is not relating to the Events post.
Btw, I am using local server called Local by Flywheel. Not sure if this causes the issues.