Worksheet BACKGROUND Colour vs Cell FILL Colour

Hi,

We have a shared workbook in our group at work, that was created on desktop Excel some time ago and is now a live document on a member's OneDrive.
It now gets edited by several people through the webapp 365 interface.
The behaviour below has been observed from before the document was taken live online.

Simply put, cutting and pasting a cell results in the original cell location turning cyan colour, rather than the general white that the rest of the worksheet is.
Seems rivial but when the workaround is to copy the cell instead and then go back to delete the contents of the original, this results in a lot of clicking around.

There doesn't appear to be any conditional formatting in the sheet at all.

I suspected that maybe there is a background colour of the entire worksheet or woorkbook and that the cells are FILLED in white.
However I can't find anywhere to adjust the background colour, or even that such a thing exists seperately to cell fill colours.

I would love the cut cell to simply turn plain white once its contents has been pasted elsewhere.

Any suggestions?

This even stumped ChatGPT :-)