We know the drummer doesn’t always tell the truth because they claim they tell a mixture of truth and lies, making it a false statement. So because we know that, the piper also can’t be telling the full truth.
So drummer cant be truth and neither can the piper. So let’s run through each one of the others in that spot.
Bear: When you mark the bear as the one who tells the truth, there isn’t enough info to figure it out. So it cannot be them.
Juggler: Once again, there really isn’t enough information to figure it out if the juggler was it.
Jester: The jester however, does have enough info for it to be the one who tells the truth, because they say the piper tells nothing but lies. That checks out, because the drummer doesn’t always tell the truth. And because the bear doesn’t always tell the truth, the juggler is a mix, as well as the rest.
So, Jester always tells the truth, the piper always lies, and the bear, the drummer, and the juggler tells a mix of truths and lies. I hope that makes sense!