Hi!
I'm using tmux 2.3 locally as terminal tabs and same version remotely (nested tmux via ssh) on archlinux and ubuntu hosts. It's works perfectly, but i have problem with terminal sequence passthrough.

In plain terminal this sequence works (it's urxvt notification):
printf %b '\033]777;notify;test;test\007\007'

In one tmux passthrought sequence works too:
printf %b '\033Ptmux;\033' '\033]777;notify;test;test\007\007' '\033\\'

By my assumption, double sequence should work in nested tmux, but it doesn't (i'm getting freezed pane instead, until i'll close connection):
printf %b '\033Ptmux;\033' '\033Ptmux;\033' '\033]777;notify;test;test\007\007' '\033\\' '\033\\'
It there any way to pass sequence through two tmux?

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TERM=tmux-256color inside, and TERM=rxvt-unicode-256color outside
% uname -sp && tmux -V && echo $TERM
Linux unknown
tmux 2.3
tmux-256color