Linux, CS 6.83
With this code and with json mentioned in first line a: () rule is skipped by CS

# :json crm-data {"error" : "rghr", "token" : "sometok_enblyat", "accounts" : [{"token": "anytoken1", "name" : "Westwood"}, {"token": "anytoken2", "name" : "Forestpaper"}] }
u: (\:json _*1 _*)
$$counter = 0
# $orjs = ^original( _1 )
$crmdata = ^jsonparse( ^original( _1 ) )
$tmp = ^jsonpath(.accounts $crmdata)
$tmp = ^length($tmp)
${tcard\: navigation-card\: {"items"\: \[
loop( $tmp )
{
\{"title"\: \" ^jsonpath(.accounts.$$counter.token $crmdata )\" \} 
  $$counter += 1
  if ($$counter < $tmp) { , }
  }
\]}$}

a: ( )
  $crmdata.error

The next code works as expected (transfer json as usual string)

u: (\:json _*1 _*)
$$counter = 0
$orjs = ^original( _1 )
$$crmdata = ^jsonparse( ^original( _1 ) )
$tmp = ^jsonpath(.accounts $$crmdata)
$tmp = ^length($tmp)
${tcard\: navigation-card\: {"items"\: \[
loop( $tmp )
{
\{"title"\: \" ^jsonpath(.accounts.$$counter.token $$crmdata )\" \} 
  $$counter += 1
  if ($$counter < $tmp) { , }
  }
\]}$}

a: ( )
  $$crmdata = ^jsonparse( $orjs )
  $$crmdata.error

This is because, by default, ^jsonparse generates transient JSON facts and so they will be deleted at the end of the volley.
As the rejoinder, the a: rule, is invoked on the next volley then $crmdata is pointing to nothing.

Your version that works is because you are storing a string in a permanent variable.

For the first version to work then you need to create permanent json facts via ^jsonparse(permanent ^original(_1)).
But be aware that you will have to take care of the cleanup and do a ^delete($crmdata) (and $crmdata = null) at some point.