I frequently do alt . in bash to repeat the last parameter of the previous line.
Recently, this stopped working. (it just prints a .)
also, in irssi, alt-number usually switches to a window. this now just echos the number key I pressed.
reproducible in gnome-shell and the xfce terminal, which is why I think it's vte at fault here.
*** This bug has been marked as a duplicate of bug 626792 ***