salt: 14.04 / salt '*' test.ping Failed to authenticate, is this user permitted to execute commands?

Since my upgrade to 14.04 and sync of @makinacorpus fork to last develop, something is weird.

I get intermittent total unfunctionnality of the saltmaster , on a period of 1 at 2 minutes, i cant ping any minion, and the next 2 minutes ping is working, and 2 minutes after this does not work.

 mastersalt '*' test.ping
Failed to authenticate, is this user permitted to execute commands?

I rebuilded all the eggs locally installed to be sure of the linking, but this seems not to be sufficient.

Ill check tomorow to double check if this is one of our maintainance crons, but i would suspect yet another regression.