In rally1.rallydev.com, on the Test Case Steps editor screen, when I enter a large block of text, I encounter this warning.
That is fine. I knew I was experimentally pushing the boundaries...
I have stripped out all formatting; I have removed special characters (that might need additional characters adding to 'escape' them or similar); I have ensured that I am in a 'clean' new Step with no inaccessible/undeletable hidden characters hanging over from my previous editing, and it seems that I can only enter approx 1600 'real' characters (including spaces) before hitting this limit.
That is fair enough, but any explanation of those 400 characters -- or however many characters might be unaccounted-for with different content -- would be valuable to me.
Please try using the Dev Tools > Inspect to check for hidden text. Please follow the steps below to repeat the steps I took in my test environment. I have added a screenshot of my "Inspect" to this case so you use this too:
1. Enter text into the rich text field. In this case it was the Test Step field.
2. Right-click in the Test Step field (or any rich text field) to display a dropdown menu
3. Select "Inspect"
4. This should put you on the "Elements" tab in the inspect and the highlighted line on the screen should put you at the verbiage you entered. You will probably have to expand the arrows to see all the text.
5. At this point you should see all the "hidden text". As a note, the <p> and <br> etc all count as characters. Essentially everything between <body> and </body> will count as a character.
These articles also have more information and ideas on how to troubleshoot this: