Ok again a similar situation. I was studying and was employed at the same time too, and I was asked for an explanation about these specific time periods in ADR and IMM5669 form.Thanks, I made an excel file with my AOR submitted personal history timeline, after checking multiple times, I found that there was no gap as I indeed filled up the period they asking for between 2009/03 and 2009/06, the only thing is that there was an Overlapping since I was working and studying at the same time, but I clearly mentioned that through personal history, I still wonder why they asked me for such form, I am nearly banding my head now because I took so much precautions not to miss anything yet they required me such form.
I received 1st LOE request on August 21st and second IMM5669 form request on Oct 16th. Hope this helps your anxiety