Symptoms
MSbuild deployment missing features folder
Diagnoses
Deploying with MSbuild is successful, but it would seem the features folder on the Sharepoint WFEs are not created
Resolution
To workaround the issue, we manually copied the appropriate feature folders to each WFEs. To resolve the root cause of this issue, you will most likely need to add another web application bindings and alternate access mappings as per the .pdf in KB:
http://help.k2.com/kb000652