Hello yllek1234,
Welcome to Community! I can understand your concern with the T4 slips, missing boxes, inaccurate information due to the missing boxes. My first suggestion is to ensure your QuickBooks Desktop is updated to the latest release, along with the payroll tax table.
If these are both up to date, I recommend downloading the QuickBooks Tool Hub and run Quick Fix my program. Should you experience the same outcome, please contact us outside of Community. It would be our pleasure to work with you in real-time, and review the unexpected behavior in more depth from our end. Your success is our number one priority and we would be glad to help!
Feel free to reach out with other questions. We're here for you!