In the US, the correct spelling is 'Gray'. In the other countries, the correct spelling is 'Grey'. Some language packs use both spellings, which is annoying when using the search feature. Here are the mistakes in various language packs:

English (UK), correct spelling should be grEy:

• grAy stained clay
• light grAy stained clay
• grAy shulker box.

English (Canada, Australia and New Zealand); correct spelling should be grEy:

• grAy shulker box.

There are no mistakes in English (US).