Bug when importing course

Hello,

I will probably submit a tracker but I want to check first that I'm not the only one experiencing this problem.

Moodle 2.3.1+ here.

When I import an assignement the students don't see the "add submission" button unless I go to the settings of the assignment and I save. I don't even have to change the seetings, just hit the 'save' button and the students see the assignment correctly.

Have any of you encountered this problem?

Thanks,

Monica