PATH="/usr/local/php74/bin:$PATH"The problem was that PHP 7.4 was being added in ~/.bash_profile which is only for login shells. The export connects with a non-login shell and so the default php was getting loaded. By placing it in ~/.bashrc it gets loaded.
*Check to see if you are using a command that is prompting for user input, e.g. drush pm-enable ... will hang unless you have the -y flag. So the correct command within a processor is drush pm-enable -y ...
processor; that is a good way to see if there are any user prompts.