I tried to re-produce the bug and found an issue with Firefox when the referrer headers are disabled in-combination with Chart.js.
Are you using Firefox, if so can you check if you disabled referrer headers?
Last time I tried it in several different browsers like Librewolf (fork of Firefox with custom settings), Firefox and Chromium with default settings plus uBlockOrigin, and I was getting the exact same issues.
However, I just checked your website again and it's working perfectly normal, loading all charts, so it must have been some temporary glitch.