Loogs, not all gaps (or windows in candlestick terms) are meant to be filled, breakaway gaps in particular. (I'm not much of a believer in gaps, with the exception that breakouts on high volume accompanied by gaps outperform breakouts without gaps... see Bulkowski's research).
Dual listed stocks create further complications. Obviously, if market sensitive news is released whilst one exchange is closed, gaps are far more common as there is a "catch up" factor when the other exchange opens.
UNS Price at posting:
81.5¢ Sentiment: Hold Disclosure: Held