I have been unable to change a capital letter in a Lingq to lower case. The software allows me to make the change. I save it. And it remains the same. I reload the page. It remains the same.
I suspect the software checks to determine if an edit was made but that it checks against a saved copy that has been rendered in all caps (or all lower case) and then compares the edit also rendered in all caps (or all lower case), hence concluding that no edit was made and that no action need be taken.