Prospective future employers may question the judgement of someone who hangs on at Avaya through this period. If there is the possibility of a large severance package at the end, then you may be able to explain why you stuck around. But if you are in a jurisdiction where severance is not being paid and probably never will be paid (USA?) you have to wonder whether someone stayed there just because they could not find employment elsewhere.
As someone who is doing the interviewing to fill positions at our company, sticking around too long when a company is clearly going under is something that would be questioned - but depending on the answer it could have no impact on the hiring decision.
This is mildly put ridiculous. People who are staying at Avaya are excellent engineers who are still well compensated and have no reason to jump ship just yet. There is no need to look for something new if the current position provides all I need at the moment, despite the issues the company has. Why in the world would you consider that a detriment in an interview, is beyond me. And as somebody already said, I would not want to work for an employer who used this as a negative in hiring process.