Many card readers had odd issues as card sizes grew. The only way to test this reader is to show it working with same make and model SD card. Just because the 8GB worked is not proof.
ChromeOS may not format the card in a Windows supported file system. My test would be to look at the card on this reader under Linux next.
First off the card is most likely not defective as it shows up and works fine in chromeos, however on windows it shows up as unopenable in file explorer and anywhere else it says its 1mb. I have checked almost everything (windows disk management, disk part and the properties of the card) I even tried updating the drivers but no luck. My card reader is also probably not the problem as it works with a smaller 8gb card. has anyone else had this problem?
Screenshots of everything saying 1mb