I am getting an error message: "The field UserInstructions must be a string or array type with a maximum length of '50000'"

This is an error that can occasionally occur with lengthier custom instructions because TurkPrime converts the text format in order for it to display properly (which adds a bunch of characters in the code and causes that error) within the HIT. We are currently working on potential solutions to this, but until then, you can simply make any change or edit (even if it is just a simple space or backspace--you don't have to delete any characters or anything) in the instructions field in order for it to recompute and you should then be able to save the study and launch without any issues.