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Disappearing Comment Bug
Main article: Disappearing Comment Bug
Mainly found in Scratch 3.0, this bug causes profile, project, or studio comments to not show when attemping to view it. Sometimes, when the message for the comment is clicked, the comment section won't load. Then, if you try to view the page where the comment is without the direct comment link, the comment will not be shown. This can cause the inability to view, reply, delete, or report the comment. To fix this, do a hard refresh.
I found it in pro123465's profile.

Another way I know to fix it is post a comment on the project/profile affected, then reload the page (you can also delete your comment afterwards if possible, as you only need to do that once.)

MeIzAwezomeDede wrote:

Another way I know to fix it is post a comment on the project/profile affected, then reload the page (you can also delete your comment afterwards if possible, as you only need to do that once.)

This does not always work.

grrr i sent two comments on a scratcher's profile AND project but neither showed up when i went back to them! >

-avocado-cat- wrote:

(#4)
grrr i sent two comments on a scratcher's profile AND project but neither showed up when i went back to them! >

This is just a glitch, wait a little bit and/or reload the page.
In addition, do not necropost.