cPanel file permissions acting up again? What gives?

Hey everyone, following up on my previous 'permission denied' post. Thought I had things sorted, but cPanel's permissions management seems to be playing whack-a-mole with me again, randomly failing file operations even after I set what I *thought* were the correct permissions. Here’s a snippet of the latest head-scratcher:

[2024-05-15 10:30:45] PHP Warning:  file_put_contents(/home/user/public_html/cache/data.json): Failed to open stream: Permission denied in /home/user/public_html/app/Processor.php on line 123

What's the trick to consistently manage permissions management on cPanel so these ghost errors stop haunting my site? Anyone faced this before?