I notice that a few of my internal links are of the format [Mynote](app://obsidian.md/mynote). In this example I cannot open the “note name” link directly by clicking on it. However, if I go to File Browser I can open “mynote” by clicking on it. I certainly don’t recall deliberately using the above format when I created the problematic links.
Thank you for the information. Out of all my internal links (I didn’t count them) I found 16 instances where there was this unusual type of link. I went through each one of them and changed them accordingly.
I see no pattern in what or why these changes took place if it was a plugin that created them. What worries me is a possible recurrence of the problem as I do not know the cause of it.