csrf token and cookie

I am having a challenge implementing csrf protection on two projects based on CI 3.x.  As far as I know, my code is not unconventional.  Submission of any form results in:

PHP Code:

An Error Was Encountered

The action you have requested is not allowed. 


I have looked at numerous solutions to such a problem posted on the web

• I am using form_open() as required for CI to automatically insert the csrf token;
  

• config elements for crsf and cookies meet the requirements
  

Here are portions of config.php:

PHP Code:

$config['base_url'] = 'http://betasite.lh.com/';

Session Variables:
$config['sess_driver']            = 'database';
$config['sess_cookie_name']        = 'ci_session';
$config['sess_expiration']        = 7200;
$config['sess_save_path']        = 'ci_sessions';
$config['sess_match_ip']        = FALSE;
$config['sess_time_to_update']         = 300;
$config['sess_regenerate_destroy']    = FALSE;

Cookie Related Variables:
$config['cookie_prefix']    = '';
$config['cookie_domain']    = '.betasite.lh.com';
$config['cookie_path']      = '/';
$config['cookie_secure']    = FALSE;
$config['cookie_httponly']  = FALSE;

Cross Site Request Forgery:
$config['csrf_protection']   = TRUE;
$config['csrf_token_name']   = 'csrftoken';
$config['csrf_cookie_name']  = 'csrfcookie';
$config['csrf_expire']       = 7200;
$config['csrf_regenerate']   = TRUE;
$config['csrf_exclude_uris'] = array(); 


What is the process of generating the token, setting it in a cookie and posting it in the hidden field in a form?  Logically, is it?:

1. generate token
   
2. save it to cookie
   
3. read token from cookie into $this->crsf_hash
   
4. place token in form so it appears in $_POST at time of form submission
   

I ask because stepping through the code with xdebug I am seeing inconsistencies.  Running a log-in without debugging and it will always fail.  On some occasions - maybe 1 out of 8 - if I step through function csrf_verify (Security.php, version CI 3.1.6) the verification passes for the hash in the cookie and the value in $_POST match.  The log-in completes as it should.

Since `$config['csrf_regenerate']  = TRUE;` is it necessary to set the csrf cookie in the controller for my application?

Thank you for taking the time to read this.