My wife has a new Specialized Crosstrail (hybrid style) bicycle.
On our last ride, she noticed that shifting up one gear using the rear derailleur would work intermittently. That is, sometimes shifting from one gear to the next would work fine, and then other times the rear derailleur would attempt to shift, get halfway there, and make a clicking noise. When this happens, she had to shift two gears up, and then back down one gear to get to the gear she wanted. It appears that shifting down from this "problem" gear, or up from it works fine.
I am new to cycling, so if you need additional information, please let me know.
I appreciate the advice.