I have an up-to-date Galaxy A51. Whenever a diagonal arrow character (↖↗↘↙) appears, it is shown with a blue background. For horizontal and vertical arrows (↑→↓←) this is not the case, they are shown with the normal background. This seems like a font issue.
I use a weather app that uses arrow characters to indicate wind direction. This is very sensible. However, because of the issue with the blue backgrounds, this looks ugly. This issue is Samsung-software specific, as I do not see it on another smartphone with less customized Android. I tested it in the Galaxy Store app's search box and share a screenshot of that below.
I think that this is a bug that needs to be fixed, but would in the meantime be very interested in a workaround.
It would be interesting to hear whether others have the same issue on the same or different Galaxy devices.