Search on Custom Field Yields False Positives

Had this happen on client site running 4.6.9 under WP and recreated it on 4.6.11 WP demo site.

Create a custom field of type checkbox. Add enough options that there are double digit values - 1,2,3,4,5,6,7,8,9,11,12, 13, etc. Use Advanced Search or Search Builder to search for one of the options in the custom field. Searching for the option that is represented by the value "1' will also return the options represented by anything that has a "1" in the value - 11,12, 13, etc., as well as 21, 31,etc. This is a regression error as this was not like this version 4.4.

You can test this on the WP demo site by searching the Search Bug Test custom field.