Post editor shows more tags than post/category pages do

[cellio]

meta:289816

I do not know if this is a one-off data error or if there is an underlying cause that we should address.

Example demonstrating the problem: https://electrical.codidact.com/posts/285721

This post displays one tag, but if you edit the post, the editor shows four tags:

• RF, the single displayed tag
• RF-switch, which the tags page shows with 0 uses
• esd and tvs, which don't exist but ESD and TVS do -- I think these were either merged or renamed

Do we need to do some extra bookkeeping when we merge or rename a tag?
When the last use of a tag is deleted, should we delete the tag if there is no description? (I did not confirm that there are no deleted uses of that one tag; I scanned the deletions page but I can't directly search for that in the UI.)
Would any of that helped in this case?

Or is this a cache problem we can't do anything to prevent in the code and we should just fix cases when found?

[MoshiKoi]

Duplicate of #268?

[cellio]

Oh right -- I remembered something like this getting fixed, but that bug is clearly open.

[cellio]

Closed as duplicate. Added this meta link to the other bug.