Getting expired token

Hi,

I have a number of jobs that connect to marketo to download or upload data via RESTAPI.

each one connects, and geta a session token:

<logsnip>

Token: b181289f-013d-4075-bda4-80a4583071a9:ab and expires in 0

So I added a check for the expiration:   and if expired, get a new token.  

try 2nd time to get a token: b181289f-013d-4075-bda4-80a4583071a9:ab returned

same expired token returned.

obvious result when using CURL:
{"requestId":"c500#153609e0084","success":false,"errors":[{"code":"602","message":"Access token expired"}]}

Why do i get an expired token, and why do i get the same expired token a 2nd time, even after checking?

This job typically runs in seconds and only grabs a few 100k of data.

Its not always the same job either.  it could be the first one of the morning, or the 3rd one, 45 minutes later.