Not exactly sure when it happened but mumble is broken in the repo. libprotobuf is running at version 22 but the version of mumble looks to need 21.
mumble: error while loading shared libraries: libprotobuf.so.21: cannot open shared object file: No such file or directory
ldd which mumble
linux-vdso.so.1 (0x00007ffc1ee5c000)
librt.so.1 => /lib/librt.so.1 (0x00007f8587c64000)
libXi.so.6 => /usr/lib/libXi.so.6 (0x00007f8587a54000)
libssl.so.1.1 => /usr/lib/libssl.so.1.1 (0x00007f85877c7000)
libcrypto.so.1.1 => /usr/lib/libcrypto.so.1.1 (0x00007f8587301000)
libprotobuf.so.21 => not found
libspeex.so.1 => /usr/lib/libspeex.so.1 (0x00007f85870e8000)
libspeexdsp.so.1 => /usr/lib/libspeexdsp.so.1 (0x00007f8586ed5000)
libopus.so.0 => /usr/lib/libopus.so.0 (0x00007f8586c79000)
libsndfile.so.1 => /usr/lib/libsndfile.so.1 (0x00007f8586a01000)
libX11.so.6 => /usr/lib/libX11.so.6 (0x00007f85866c6000)
libasound.so.2 => /usr/lib/libasound.so.2 (0x00007f85863d6000)
libpulse.so.0 => /usr/lib/libpulse.so.0 (0x00007f8586185000)
libdns_sd.so.1 => /usr/lib/libdns_sd.so.1 (0x00007f8585f7c000)
libavahi-common.so.3 => /usr/lib/libavahi-common.so.3 (0x00007f8585d6f000)
libavahi-client.so.3 => /usr/lib/libavahi-client.so.3 (0x00007f8585b5e000)
libpthread.so.0 => /lib/libpthread.so.0 (0x00007f858593e000)
libQt5Svg.so.5 => /usr/lib/libQt5Svg.so.5 (0x00007f85856e8000)
libQt5Widgets.so.5 => /usr/lib/libQt5Widgets.so.5 (0x00007f8584e7f000)
libQt5Gui.so.5 => /usr/lib/libQt5Gui.so.5 (0x00007f85846db000)
libQt5Network.so.5 => /usr/lib/libQt5Network.so.5 (0x00007f858432b000)
libQt5Sql.so.5 => /usr/lib/libQt5Sql.so.5 (0x00007f85840e1000)
libQt5Xml.so.5 => /usr/lib/libQt5Xml.so.5 (0x00007f8583ea2000)
libQt5DBus.so.5 => /usr/lib/libQt5DBus.so.5 (0x00007f8583c0d000)
libQt5Core.so.5 => /usr/lib/libQt5Core.so.5 (0x00007f85834d5000)
libGL.so.1 => /usr/lib/libGL.so.1 (0x00007f8583267000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f8582e8e000)
libm.so.6 => /lib/libm.so.6 (0x00007f8582b4d000)
libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007f8582935000)
libc.so.6 => /lib/libc.so.6 (0x00007f858257a000)
libXext.so.6 => /usr/lib/libXext.so.6 (0x00007f8582368000)
libz.so.1 => /usr/lib/libz.so.1 (0x00007f858214f000)
libdl.so.2 => /lib/libdl.so.2 (0x00007f8581f4b000)
libFLAC.so.8 => /usr/lib/libFLAC.so.8 (0x00007f8581d0e000)
libogg.so.0 => /usr/lib/libogg.so.0 (0x00007f8581b05000)
libvorbis.so.0 => /usr/lib/libvorbis.so.0 (0x00007f85818d9000)
libvorbisenc.so.2 => /usr/lib/libvorbisenc.so.2 (0x00007f8581630000)
libxcb.so.1 => /usr/lib/libxcb.so.1 (0x00007f858140a000)
/lib64/ld-linux-x86-64.so.2 => /lib/ld-linux-x86-64.so.2 (0x00007f8587e6c000)
libpulsecommon-13.0.so => /usr/lib/pulseaudio/libpulsecommon-13.0.so (0x00007f8581188000)
libdbus-1.so.3 => /usr/lib/libdbus-1.so.3 (0x00007f8580f37000)
libpng16.so.16 => /usr/lib/libpng16.so.16 (0x00007f8580d01000)
libharfbuzz.so.0 => /usr/lib/libharfbuzz.so.0 (0x00007f85809ff000)
libsystemd.so.0 => /usr/lib/libsystemd.so.0 (0x00007f8580749000)
libicui18n.so.64 => /usr/lib/libicui18n.so.64 (0x00007f8580265000)
libicuuc.so.64 => /usr/lib/libicuuc.so.64 (0x00007f857fe96000)
libicudata.so.64 => /usr/lib/libicudata.so.64 (0x00007f857e254000)
libpcre2-16.so.0 => /usr/lib/libpcre2-16.so.0 (0x00007f857dfd3000)
libzstd.so.1 => /usr/lib/libzstd.so.1 (0x00007f857dd1f000)
libgthread-2.0.so.0 => /usr/lib/libgthread-2.0.so.0 (0x00007f857db1d000)
libglib-2.0.so.0 => /usr/lib/libglib-2.0.so.0 (0x00007f857d7fd000)
libglapi.so.0 => /usr/lib/libglapi.so.0 (0x00007f857d5c8000)
libdrm.so.2 => /usr/lib/libdrm.so.2 (0x00007f857d3b7000)
libxcb-glx.so.0 => /usr/lib/libxcb-glx.so.0 (0x00007f857d19e000)
libX11-xcb.so.1 => /usr/lib/libX11-xcb.so.1 (0x00007f857cf9c000)
libxcb-dri2.so.0 => /usr/lib/libxcb-dri2.so.0 (0x00007f857cd97000)
libXfixes.so.3 => /usr/lib/libXfixes.so.3 (0x00007f857cb91000)
libXdamage.so.1 => /usr/lib/libXdamage.so.1 (0x00007f857c98e000)
libXxf86vm.so.1 => /usr/lib/libXxf86vm.so.1 (0x00007f857c788000)
libexpat.so.1 => /usr/lib/libexpat.so.1 (0x00007f857c55d000)
libxcb-dri3.so.0 => /usr/lib/libxcb-dri3.so.0 (0x00007f857c359000)
libxcb-present.so.0 => /usr/lib/libxcb-present.so.0 (0x00007f857c156000)
libxcb-sync.so.1 => /usr/lib/libxcb-sync.so.1 (0x00007f857bf4f000)
libxshmfence.so.1 => /usr/lib/libxshmfence.so.1 (0x00007f857bd4d000)
libXau.so.6 => /usr/lib/libXau.so.6 (0x00007f857bb49000)
libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0x00007f857b943000)
libasyncns.so.0 => /usr/lib/libasyncns.so.0 (0x00007f857b73d000)
libfreetype.so.6 => /usr/lib/libfreetype.so.6 (0x00007f857b494000)
libgraphite2.so.3 => /usr/lib/libgraphite2.so.3 (0x00007f857b268000)
liblzma.so.5 => /usr/lib/liblzma.so.5 (0x00007f857b042000)
liblz4.so.1 => /usr/lib/liblz4.so.1 (0x00007f857ae10000)
libcap.so.2 => /usr/lib/libcap.so.2 (0x00007f857ac0b000)
libgcrypt.so.20 => /usr/lib/libgcrypt.so.20 (0x00007f857a8f0000)
libpcre.so.1 => /usr/lib/libpcre.so.1 (0x00007f857a67e000)
libnsl.so.1 => /lib/libnsl.so.1 (0x00007f857a467000)
libresolv.so.2 => /lib/libresolv.so.2 (0x00007f857a250000)
libbz2.so.1.0 => /usr/lib/libbz2.so.1.0 (0x00007f857a03f000)
libgpg-error.so.0 => /usr/lib/libgpg-error.so.0 (0x00007f8579e1f000)
`----------------------------------------------------------------------------------------------------------
cat /var/log/pacman.log
...
[2019-10-22 20:41] [ALPM] upgraded xorgproto (2019.1-1 -> 2019.1-3)
...
[2019-10-22 20:41] [ALPM] upgraded protobuf (3.7.1-1 -> 3.9.2-1)
...
[2019-11-17 19:37] [ALPM] upgraded protobuf (3.9.2-1 -> 3.10.1-1)
...
[2019-12-02T09:03:27-0500] [ALPM] upgraded protobuf (3.10.1-1 -> 3.11.0-1)
`