can't switch input language after ibus upgrade

Description: Ubuntu 14.04.3 LTS
Release: 14.04

The following package updates break switching the input language:

Upgrade: libibus-1.0-5:amd64 (1.5.5-1ubuntu3, 1.5.5-1ubuntu3.2), gir1.2-ibus-1.0:amd64 (1.5.5-1ubuntu3, 1.5.5-1ubuntu3.2), python-ibus:amd64 (1.5.5-1ubuntu3, 1.5.5-1ubuntu3.2), ibus-gtk:amd64 (1.5.5-1ubuntu3, 1.5.5-1ubuntu3.2), ibus:amd64 (1.5.5-1ubuntu3, 1.5.5-1ubuntu3.2), ibus-gtk3:amd64 (1.5.5-1ubuntu3, 1.5.5-1ubuntu3.2)

reverting the above fixes it:

Downgrade: libibus-1.0-5:amd64 (1.5.5-1ubuntu3.2, 1.5.5-1ubuntu3), gir1.2-ibus-1.0:amd64 (1.5.5-1ubuntu3.2, 1.5.5-1ubuntu3), python-ibus:amd64 (1.5.5-1ubuntu3.2, 1.5.5-1ubuntu3), ibus-gtk:amd64 (1.5.5-1ubuntu3.2, 1.5.5-1ubuntu3), ibus:amd64 (1.5.5-1ubuntu3.2, 1.5.5-1ubuntu3), ibus-gtk3:amd64 (1.5.5-1ubuntu3.2, 1.5.5-1ubuntu3)

Strangely enough, it looks as if it is still working, "dconf watch /" still shows /desktop/ibus/general/engines-order getting updated, everything looks fine, except the keyboard layout has not changed.

$ gsettings get org.freedesktop.ibus.general engines-order
['xkb:us::eng', 'xkb:us:intl:eng']