The incorrect mapping of @ and " when using software that combines Mac and Windows is one of the oldest bugs in computing, actually more accurately it is a bug that is regularly re-created by new generations of sadly stupid, ignorant American programmers. 👿
I say American because this problem typically does not happen if you are using a US keyboard layout on the Mac to communicated with a US keyboard layout in Windows. It does happen for example with a UK to UK layout and I believe all non-American keyboard layouts.
It has affected Virtual PC, Microsoft Remote Desktop Client, Timbuktu Pro, and many many others, the commonality being that they were written by American programmers. I believe VNC, at least the original version was not affected because it was originally written at AT&T labs in Cambridge, England and not Cambridge, Massachusetts i.e. by English programmers who realise that the world is not flat and that if you leave the US you do not fall of the edge of the world. Remember that one of the first people to sail around the world was an Englishman - Captain James Cook, so we English at least know the world is not flat even if Americans remain firmly geographically challenged. 👿 We English also know that the Discworld series of books by Sir Terry Pratchett are works of fiction.
I have not thoroughly checked using Windows 10 and Boot Camp and any keyboard layout issues but historically Apple have despite having the misfortune of using American programmers been far better at coping with non-US keyboard layouts than other companies. My Windows 7 Boot Camp setup for example has no problems at all when using a UK keyboard. Apple even provide proper support for using Windows keyboards on a Mac, for example not only do Apple provide a British keyboard layout for using a Mac British keyboard, but they also provide a British PC keyboard layout for using a Windows British keyboard on a Mac. This is because Apple realise unlike so many other American programmers that not only are other country keyboards different layouts but also that PC and Mac keyboard layouts are also different.
I would advise double-checking the keyboard settings in Windows 10 and making sure it is set to UK layout - this presumes you have a UK keyboard. It might be worth also checking to see if Windows lists both standard Windows and Mac layouts. It is possible Apple 'install' Mac keyboard layouts in to Windows as part of their Boot Camp drivers.
Note: The basis for the American repeated programming error is that they do not do the obvious step of 'listening' for a character from the keyboard they instead listen for a key in a particular location which might have a specific key identifier number and just send that identifier. This of course completely falls down when you use a different layout. It is lazy, stupid and guaranteed to cause this problem. This is compounded by their failing to consider other layouts and assuming only US layouts exist.
As an example of how generation after generation of American programmers keep making this same mistake -
Microsoft Remote Desktop Client for Mac version 1.x had this bug
Microsoft Remote Desktop Client for Mac version 2.x fixed this bug
(there was no version 3 to 6)
Microsoft Remote Desktop Client for Mac version 7.x returned this bug
Microsoft Remote Desktop Client for Mac version 8.x still has this bug
Note: While @ and " are the ones most people instantly spot, it is also typically not possible to generate a \ (backslash) when hit by this 'bug'. As Windows uses a backslash a lot this is particularly frustrating.