command-line: nodeJS not working on double-pipelining (solved)

I'm trying to execute my node app through a bash script using some pipes to have a nice formatted output:

node ~/app.js 2>&1 | grep -v "something" | grep --color -Ei "^|Error"

But I got a frozen output.

Everything is nice when I type node ~/app.js | command_1, the problem seems to appear when using node ~/app.js | command_1 | command_2.

No problem with other commands like cat myscript.sh | command_1 | command_2

I'm using node v0.10.15 and ubuntu 13.10 server.

TL;DR: No output from node ~/app.js | command_1 | command_2

How to handle this problem?

Say me if my question is not clear.