I did not live in NY state nor is my company HQ'd in NY state, but I did travel there for work. NY state is now asking for taxes. What do I do?

Just received a letter from NY saying I owe a large penalty for not filing NY state taxes in 2018.

1. At this time, I was not living in NY (domiciled in a different state)

2. I did not stay in NY >183d

3. My company is not HQ'd in NY (it is based in CA). 

 

However, I did travel there semi frequently for work (maybe 8-10 weeks in the year). I checked and it turns out my employer did create a W2 for me in NY but I'm not sure why. Any advice? Do I have a reason to object or is the sad reality that I did, in fact, owe taxes?