I contributed 299.28 / year for yeara toward my pension and GE says that amount is non taxable. TTX now says it is taxable just this year, but never before. What gives?

I worked for GE for 18 years. 28 years later, my total contributions somehow becomes taxable all in one year? TTX system says I have to use the Simplified Method. The taxable amount this year is within a few hundred dollars of my entire annual pension. I don't smoke or drink but I think the programmer for this section just might? How do I fix this and how do I find out what others think?