_CT records with identical __$seqval

There is a CDC enabled table of the following form:

create table dbo.foo (
    id int not null primary key,
    a char(1), 
    b char(1), 
    c char(1), 
    d char(1), 
    e char(1),
    updated datetime not null default getdate(),
    active bit not null default 1
);
go

When querying cdc.dbo_foo_CT, I see the paired records of the following form (_note differences in columns a & updated_): | __$start_lsn | __$end_lsn | __$seqval | __$operation | __$update_mask | id | ⭐a | b | c | d | e | ⭐updated | active | __$command_id | |---|---|---|---|---|---|---|---|---|---|---|---|---|---| | 0x02 | _NULL_ | 0x01 | 1 | 0xFF | 1 | a | b | c | _NULL_ | _NULL_ | 12:00:00 | 1 | 1 | | 0x02 | _NULL_ | 0x01 | 2 | 0xFF | 1 | x | b | c | _NULL_ | _NULL_ | 13:00:00 | 1 | 2 | Given [operations 1 & 2](https://learn.microsoft.com/en-us/sql/relational-databases/system-tables/cdc-capture-instance-ct-transact-sql) are delete & insert respectively, I might otherwise expect this to be a full-row delete-then-reinsert pattern from an app; _but_ there are identical values in _both_ __$start_lsn & __$seqval. When attempting to repro a delete/re-insert in a transaction, the __$seqval still increments AFAICT. Notably a merge command produces the delete/re-insert CDC pattern but still increments the __$seqval as expected. CDC was only recently enabled, and _every_ record in cdc.dbo_foo_CT is a paired record of this form although other CDC enabled tables in the same database do not show this pattern. What could be causing this behavior?