They are talking a sore point

他们在讨论一个惹人恼怒的话题

Specifically, the siege maps remain a sore point.

尤其是围困地图仍旧很困难。

It's a sore point with Sue's parents that the children have not been baptized yet.

让苏的父母很伤心的是孩子们至今还没受洗礼。