Audacity adds ".aiff" expension to all exported audio

Upon exporting audio files, Audacity attempts to add .aiff to every file name (regardless of the type of file export). The expected behavior would be to either (a) not append a file extension in the save dialog, or (b) add the extension of the export format.

To reproduce: just choose to export an audio file.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: audacity 2.1.2-2
ProcVersionSignature: Ubuntu 4.10.0-26.30-generic 4.10.17
Uname: Linux 4.10.0-26-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
CurrentDesktop: Unity:Unity7
Date: Tue Jul 11 00:36:11 2017
InstallationDate: Installed on 2017-06-22 (19 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: audacity
UpgradeStatus: No upgrade log present (probably fresh install)