Hello,
I have noticed our logo on Google search is like this:
Where can I change this in the back end? Is it Square Logo?
Thanks 
AI-generated summary
Google Search icon discussion revolves around Joe_F trying to change the logo displayed on Google search results. Arkshine suggests that the issue might be related to the Favicon, but Joe_F clarifies that his Favicon is correct. Arkshine then suggests that the logo used is the Apple touch icon. After Joe_F updates the Favicon, Apple Touch, and Square Logo to the same image, the issue persists (Joe_F). Arkshine recommends asking Google to recrawl the URLs, as other search engines like DuckDuckGo show the correct icon, while Bing displays a generic one.
My favicon is correct and that is a totally different logo, that’s what has thrown me off.
It seems to use the Apple touch icon. Is that correct?
I can see on your site it matches this image.
Did you update Square Logo, or only Favicon?
Favicon, Apple Touch and Square Logo are all now the same logo.
Will monitor and share back if it updates
I left this over the weekend and made the changes to the above logos and it is still the same 
I don’t know how often Google refreshes the cache. You can likely ask Google to recrawl your URLs: Ask Google to Recrawl Your Website | Google Search Central | Documentation | Google for Developers
Looking at another search engine, for example, DuckDuckGo or Qwant, it shows the right icon:
Bing shows a generic icon.