First sequence number in NEW_CONNECTION_ID frame when preferred_address parameter isn't sent

[Jaikiran Pai]

Hello everyone,

I am looking for some inputs on the sequence number value that gets sent 
in a NEW_CONNECTION_ID frame. Specifically, section 5.1.1 of RFC-9000 
https://www.rfc-editor.org/rfc/rfc9000#issue-cid states:

Each connection ID has an associated sequence number to assist in 
detecting when NEW_CONNECTION_ID or RETIRE_CONNECTION_ID frames refer to 
the same value.
...
The sequence number of the initial connection ID is 0. If the 
preferred_address transport parameter is sent, the sequence number of 
the supplied connection ID is 1.
...
Additional connection IDs are communicated to the peer using 
NEW_CONNECTION_ID frames ... The sequence number on each newly issued 
connection ID MUST increase by 1.

So, sequence numbers 0 and 1 are reserved for initial connection id and 
preferred_address connection id. However, the preferred_address 
transport parameter is optional. Consider the case where the endpoint 
doesn't send the preferred_address transport parameter. Does it mean 
that it is then allowed to use a sequence number of 1 in the 
NEW_CONNECTION_ID frame that it might send subsequently? Or, is that 
sequence number only meant to be used for preferred_address parameter 
and the endpoint must start with 2 as the sequence number for any 
NEW_CONNECTION_ID frame it sends?

-Jaikiran