Works perfectly fine in my tests. Under the Filters tab of my userlist the following have been tested.
Field: cb_checkbox
Operator: Contains
Value: Option1
Results in the following.
Code:
AND ( `cb_checkbox` LIKE '%Option1%' )
Field: cb_checkbox
Operator: Does not contain
Value: Option1
Results in the following.
Code:
AND ( ( `cb_checkbox` NOT LIKE '%Option1%' OR `cb_checkbox` IS NULL ) )
Works fine combining the two as well.
Code:
AND ( `cb_checkbox` LIKE '%Option1%'
AND ( `cb_checkbox` NOT LIKE '%Option2%' OR `cb_checkbox` IS NULL ) )
Your instance of ((cb_Options LIKE 'Option1')) was probably due to a search on the userlist and not a filter. Searching the userlist with simple "is" search mode will result in no wildcards.