Integration Zendesk-Youtrack

Hi, I´ve an integratión problem between Zendesk and Youtrack.

When I put a comment in a Zendesk Ticket, everyone arrives to Youtrack card in time, but when I make the opposite, Youtrack only send the penultimate but not the last one.
If I put another note in Youtrack Card, again the sistem post the penultimate note as it had been frozen, but not the ultimate.

I have Youtrack 6.0, what´s the problem with the configuration?

Thanks in advance.
Regards,

Iván Roces.