check SSL certificate expiration date

We recently updated our SSL certificate for another year. However I am confused when check for the success of the new implementation:

-- When I checked with 
> echo | openssl s_client -servername mysite.org -connect mysite.org:443
It says "notAfter=Feb 11 23:59:59 2022 GMT" (old SSL date);

-- When I checked with Firefox to visit https://www.mysite.org, then went to
   -> Tools -> Page info -> Security -> view certificate, it says the same date
   Not After :: Fri, 11 Feb 2022 23:59:59 GMT (old SSL date);
   (repeatable even after I cleared all cache)

-- However when I checked with a web service https://www.sslchecker.com/sslchecker and it finds the updated date "Expiration date: Feb 01, 2023" (new SSL date).

Could someone advice why the 'openssl' and Firefox gave bogus results and what I should look for a reliable SSL checker tool?

Thank you in advance,
j