If your employer pays the premiums for your short-tern disability at no cost to you, then it will be taxable to you when received.
If you paid the premiums for your short-term disability out of untaxed money, then the income payments will be taxable to you when received.
If you paid the premiums for your short-term disability out of taxed (after-tax money), then your short term disability payments received should be tax free.
If it does not look correct to you, you should discuss it with your employer to verify.
