Server error caught in logs: `M_INVALID_PARAM: MatrixError: [400] event_id $redacted01 is not related to thread $redacted02`

### Steps to reproduce

1. Have someone else send a message in a large encrypted room
2. Having just started the app, send the first reply in the thread
3. Open JS console while a new Megolm outbound session is established
4. When the message does eventually send, note errors in console

### Outcome

#### What did you expect?

* No errors (this may be a race condition server-side)
* No read receipts to be sent for my own events
* Fewer than 7 http requests for this read receipt, particularly when it returns a 400 Bad Request http error

#### What happened instead?

The above. Details (should be) in the attached rageshake.

### Operating system

Windows 11

### Application version

Element Nightly version: 0.0.1-nightly.2023052201 Olm version: 3.2.14

### How did you install the app?

The Internet

### Homeserver

t2l.io

### Will you send logs?

Yes