extractGroups() documented to return array of arrays but does not

[theory]

The docs for extractGroups show this example:

WITH '< Server: nginx
< Date: Tue, 22 Jan 2019 00:26:14 GMT
< Content-Type: text/html; charset=UTF-8
< Connection: keep-alive
' AS s
SELECT extractGroups(s, '< ([\\w\\-]+): ([^\\r\\n]+)');

Returning this output

[['Server','nginx'],['Date','Tue, 22 Jan 2019 00:26:14 GMT'],['Content-Type','text/html; charset=UTF-8'],['Connection','keep-alive']]

But that's not what I see in 26.2:

Mac :) select version();

SELECT version()

Query id: f93a03ba-8f5c-4855-b3fd-821e449f8e75

   ┌─version()───┐
1. │ 26.2.1.1139 │
   └─────────────┘

1 row in set. Elapsed: 0.001 sec. 

Mac :) WITH '< Server: nginx
< Date: Tue, 22 Jan 2019 00:26:14 GMT
< Content-Type: text/html; charset=UTF-8
< Connection: keep-alive
' AS s
SELECT extractGroups(s, '< ([\\w\\-]+): ([^\\r\\n]+)');

WITH '< Server: nginx\n< Date: Tue, 22 Jan 2019 00:26:14 GMT\n< Content-Type: text/html; charset=UTF-8\n< Connection: keep-alive\n' AS s
SELECT extractGroups(s, '< ([\\w\\-]+): ([^\\r\\n]+)')

Query id: f7279dc1-49e0-4a3a-9b16-d852c23f77ee

   ┌─extractGroup⋯\\r\\n]+)')─┐
1. │ ['Server','nginx']       │
   └──────────────────────────┘

1 row in set. Elapsed: 0.002 sec. 

Here it returns only the first group. Is there some setting that affects this behavior?