The info that it's not a Chinese unit was important. Try leaving both loaded but with only the Chinese map selected leaving the English one unchecked in myMaps and you can then seach by POI at least. This post by syzygy will explain further: [Only registered and activated users can see links. ].
Quote Originally Posted by syzygy View Post
Yes, loading multiple maps of the same area will have their POIs combined, even when some maps are unchecked in the Tools setting. This trick is used by some people in China.

What happened is: they bought or brought back a foreign (outside of China) Garmin GPS device which can display maps in Simplified Chinese, but has no way to input Chinese for searching. Without searching capability, the device is close to useless. To enable searching, they actually install two CN China maps, one in Simplified Chinese and one in English. The latter is unchecked all the time. Now, to search a POI they simply enter its English name in PinYin and the POI found will be displayed on the Simplified Chinese map, ready for navigation.

There seems to be no problems reported so far with two such CN China maps installed.