Missionary Application Error Message

[alecrwatson]

When entering information under the "Additional Health Information" page, one section is not saving. We occasionally (not every time!) get a message in red that states "You have entered characters that are invalid for this data type". We do not have any unusual letters/symbols, and have even gone so far as to remove the following symbols which shouldn't be an issue: / % ; :

Even with removing these, it is refusing to save the text. We have tried multiple times. What are we doing wrong?