We faced a unique issue where user’s email was moving to Junk folder. It was noticed that this junk folder is not the
default Junk folder but a new Junk folder got created. We had troubleshooted the issue in different directions but
finally we came to the conclusion that it is due to active sync as if we disable active sync for the user, this issue
no longer occurs.
We have found that it was due to Samsung Galaxy S4 settings:
Select General Settings
Select Spam addresses
Remove any addresses that you think should not be present here. ( we found that our domain was present there)