Fatal Error on Site caught error Security plugin

Hi, I’ve been getting these errors randomly from time to time over the last 2 – 3 weeks. I’ve found nothign wrong, and after I login, I can login without any problem. BUT, sometimes I do get a Critical Error page, and after refreshing the page it loads perfectly fine. I’ve no idea what is going on but it’s been happening in my 2 sites I have under my suscription with Clean Talk.

Below is the email I received from one of the websites, the emails I’ve been receiving from time to time:

WordPress has a built-in feature that detects when a plugin or theme causes a fatal error on your site, and notifies you with this automated email.

In this case, WordPress caught an error with one of your plugins, Security by CleanTalk.

First, visit your website (https://theprogspace.com/) and check for any visible issues. Next, visit the page where the error was caught and check for any visible issues.

Error Details
=============
An error of type E_ERROR was caused in line 297 of the file /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Scanner/HeuristicAnalyser/Modules/Variables.php. Error message: Uncaught Error: Call to a member function append() on array in /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Scanner/HeuristicAnalyser/Modules/Variables.php:297
Stack trace:
#0 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Scanner/HeuristicAnalyser/HeuristicAnalyser.php(379): CleantalkSP\Common\Scanner\HeuristicAnalyser\Modules\Variables->updateVariablesEquation()
#1 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Scanner/HeuristicAnalyser/Controller.php(63): CleantalkSP\Common\Scanner\HeuristicAnalyser\HeuristicAnalyser->processContent()
#2 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Scanner/HeuristicAnalyser/Controller.php(31): CleantalkSP\Common\Scanner\HeuristicAnalyser\Controller->scanFileForHeuristic()
#3 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/SpbctWP/Scanner/ScannerQueue.php(1497): CleantalkSP\Common\Scanner\HeuristicAnalyser\Controller->scanFile()
#4 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/SpbctWP/Scanner/ScannerQueue.php(192): CleantalkSP\SpbctWP\Scanner\ScannerQueue->heuristic_analysis()
#5 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/inc/spbc-scanner.php(57): CleantalkSP\SpbctWP\Scanner\ScannerQueue::controllerBackground()
#6 [internal function]: spbc_scanner__controller()
#7 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Cron.php(121): call_user_func()
#8 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/lib/CleantalkSP/Common/Cron.php(54): CleantalkSP\Common\Cron->runTasks()
#9 /home/u453386864/domains/theprogspace.com/public_html/wp-content/plugins/security-malware-firewall/security-malware-firewall.php(370): CleantalkSP\Common\Cron->execute()
#10 /home/u453386864/domains/theprogspace.com/public_html/wp-settings.php(526): include_once('/home/u45338686...')
#11 /home/u453386864/domains/theprogspace.com/public_html/wp-config.php(79): require_once('/home/u45338686...')
#12 /home/u453386864/domains/theprogspace.com/public_html/wp-load.php(50): require_once('/home/u45338686...')
#13 /home/u453386864/domains/theprogspace.com/public_html/wp-login.php(12): require('/home/u45338686...')
#14 {main}
  thrown

And just now trying to login to my other website I get the critical error message once again (2 times by trying to login)

The page I need help with: [log in to see the link]