I have created a new superflat world with creative mode. I picked up a grass block by middle clicking on the ground and the top of the block in my hand has no color. This issue does not occur with any other block.
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Thank you for your report!
We're actually already tracking this issue in MC-161841, so I resolved and linked this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
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