Hidden Library items in EndNote 20?

Hi, I seemed to encounter a problem after merging 2 Word files with different EndNote library. The library items are suddenly all missing? but when I click one of the references, the detail information of the reference is showing (screenshot below)

I also noticed the library items were showing perfectly fine when I used the CWYW feature in Word.

I’ve already updated my version to EndNote 20.6 and the problem is still persist.

I would greatly appreciate any help!
Thank you,
Best regards