What to do if the Redmi Buds 6 Lite does not disconnect after being placed in the charging case with the lid closed?

Check if there are any foreign objects or dirt between the copper post of the earbuds and the pogo pin of the charging case. This will affect the signal transmission between the earbuds and the copper post, causing the earbuds not to be disconnected when the lid is closed. You can use a cotton swab to wipe the position of the copper post.
Note:
Although the Redmi Buds 6 Lite supports IP54 rating, it is not recommended to rinse it with water for cleaning. Please wipe gently with a cotton swab or a small amount of alcohol.