1. It's because the attachment images are parsed from the attachment itself, and it is not supported by wordpress. Unfortunately it's not possible to show the attachment images on the wordpress search results page.
2. Interestingly, if I select a different search instance (3 or 4) then it works for some magical reason. I will try to re-create this issue on my test environment to see why this happens. In case I don't find anything, I might need temporary FTP access to do the debugging on your site directly.
3. It might be the same as the previous one, if you were using the Visual Composer. If there is a bug with the search bar shortcode with VC, then there is most likely a bug with the remaining ones as well.
I'll get back to you if I find anything regarding the VC shortcodes.Best,
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