Pathfinder Simple Sheet Skill Error

On my pathfinder skill sheets, on some characters, the total column on the skill section is bugging out. the total value is changing from a single number to an equation such as(0 + 1 + 0 + 0 - -4 - 0). whenever my PCs try to roll these skills they get ReferenceError: Invalid left-hand side expression in postfix operation as an error message. it isnt happening to all my characters and more skills are randomly getting this error. HALP

I figured it out! they had heir AC penalty as a negative number, which was causing the double negative in the expression. changing the penalty to a positive number fixed the problem.