I am outside US > 6months, is it necessary to get payroll and taxes withheld in US?

[mudabagila]

Hello,

My L1B is active till Jun-2019, but I have to leave US for more than 6months for a project work in Asia this year-2018

So if I want to go back to US in Jan-Feb 2019

1. Is it necessary to be on US payroll to keep my L1B active?
And
2. Is it necessary to get my taxes withheld (including social security/medicare) in the US to keep my L1B active?

Or is it a violation of L1B if I do not get my payroll and taxes withheld in the US?

Thank you :-)