When switching to another item while drinking a potion, the item is replaced with an empty bottle and the slot with the potion is cleared

Can confirm.

Thank you for your report!
We're actually already tracking this issue in MC-159429, 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.

Scratch what I said above, this is actually a different issue.

Can confirm as well. Tricky to reproduce. The most easy way is to drink a water bottle and switch to another one while drinking. But I was able to reproduce with switching to non-consumables as well, though that is more difficult to time.