[Bug] org.apache.bookkeeper.mledger.ManagedLedgerException$CursorNotFoundException: ManagedCursor not found

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Read release policy

- [X] I understand that unsupported versions don't get bug fixes. I will attempt to reproduce the issue on a supported version of Pulsar client and Pulsar broker.

### Version

pulsar 2.8.1

### Minimal reproduce step

zk full GC

zk 挂掉后，导致
borker无法与bookie建立连接

### What did you expect to see?

question1: why zookeeper full gc?
question2: why broker not connect bookie?

### What did you see instead?

I don't know to troubleshoot

### Anything else?

_No response_

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Start with the reported Pulsar 2.8.1 reproduction: ZooKeeper full GC, the ManagedCursor-not-found exception, and the broker-to-bookie connection failure. Reproduce or inspect the attached logs and screenshots to establish why ZooKeeper enters full GC and why the broker cannot connect to the bookie; done means both causes and a verified fix or documented resolution are established.

Written by the indexing model from the issue text.