bootstrap-select doesn't work as expected from 1.13.9 version
Tested on both 1.13.9 and 1.13.10 versions, in observation page when user tries to use results filter, bootstrap-select in some cases allows him to select more than one option in each group. However the max selections per group has been defined to 1.
If the user closes and opens again the menu then the selection is right, so probably is only a UI issue and not a functional one.