Only one of my player character's gets this error when trying to roll for a skill check like perception: SyntaxError: Expected "(", ".", "[", "abs(", "ceil(", "d", "floor(", "round(", "t", "{", [ |\t], [+|\-] or [0-9] but end of input found. Everything else like attack rolls, saving throws and initiative works. Tools don't work either. It just started acting up suddenly in the middle of a test session.