I can confirm this issue (on Jessie), and would like to add that I'm experiencing it in the opposite direction from the other posters (i.e. I already had libaudio2:amd64 installed, and run into the conflict when trying to install libaudio2:i386). This is to be expected given the nature of the conflict, but thought I'd contribute anyways in the event it's useful:
Preparing to unpack .../libaudio2_1.9.4-1+b1_i386.deb ... Unpacking libaudio2:i386 (1.9.4-1+b1) ... dpkg: error processing archive /var/cache/apt/archives/libaudio2_1.9.4-1+b1_i386.deb (--unpack): trying to overwrite shared '/usr/share/doc/libaudio2/changelog.Debian.gz', which is different from other instances of package libaudio2:i386 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing: /var/cache/apt/archives/libaudio2_1.9.4-1+b1_i386.deb E: Sub-process /usr/bin/dpkg returned an error code (1)