Just checked it out and it still happens on 20.04:
sudo /usr/lib/nagios/plugins/check_running_kernel WARNING: Running kernel does not match on-disk kernel image: [Linux version 5.8.0-63-generic (buildd@lgw01-amd64-035) (gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #71~20.04.1-Ubuntu SMP Thu Jul 15 17:46:08 UTC 2021 != Linux version 5.8.0-63-generic (buildd@lgw01-amd64-035) (gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #71~20.04.1-Ubuntu SMP Thu Jul 15 17:46:08 UTC 2021 (Ubuntu 5.8.0-63.71~20.04.1-generic 5.8.18)
Just checked it out and it still happens on 20.04:
sudo /usr/lib/ nagios/ plugins/ check_running_ kernel lgw01-amd64- 035) (gcc (Ubuntu 9.3.0-17ubuntu1 ~20.04) 9.3.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #71~20.04.1-Ubuntu SMP Thu Jul 15 17:46:08 UTC 2021 != Linux version 5.8.0-63-generic (buildd@ lgw01-amd64- 035) (gcc (Ubuntu 9.3.0-17ubuntu1 ~20.04) 9.3.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #71~20.04.1-Ubuntu SMP Thu Jul 15 17:46:08 UTC 2021 (Ubuntu 5.8.0-63. 71~20.04. 1-generic 5.8.18)
WARNING: Running kernel does not match on-disk kernel image: [Linux version 5.8.0-63-generic (buildd@