Suddenly UC start wiping out every tech hunter shop in their town, why is this happen?

Whenever I go in to UC town, war between tech hunter and UC immediately start, because of how much UC guard are there, tech hunter always lose. Why is this happen?

I try provide as much information as I can

• I have 100 relationship with UC
• negative 15 relationship with tech hunter, but they not hostile towards me
• I did imprisoned a tech hunter skeleton as training dummy, but still tech hunter not hostile towards me.