Did you forget to use the pob-wotw tag the first instance you clicked the published button, and then when you remembered, you tried editing and fixing it?

Well, it would not show up if that is what happened. I don't know why, but someone I know had this experience once and that was because of what I just asked you

According to him, he figured, no, he guessed, tags are visible, active, and applicable if used at the first time of posting. And that if one edits his posts and tries editing tags, the corrections on the tags will not reflect.

the corrections on the tags will not reflect.

Here I don't mean you won't see the tag on your post. You will. Only that the audience won't see your post as one of the content using the tag. Except, of course, they are your followers or going through a new feed at that point

I hope you understand