Makerbot Z18 First Layer Issue

[jjrennel]

As stated in the title, I am using a Makerbot Z18 with firmware 1.7.1.305

I attached an image of a problem that has started up recently (I have had successful prints in the past with this machine) with the larger prints with a base 4"x 4". It happens with smaller prints as well, but do not disrupt the printing due to its limited scope. What is appears to me is that the first layer after the raft is complete is pulling up either due to lack of sticking to the raft of cooling too quickly. I have not figured out what adjustments I need to make to resolve this issue. Have any of you had this and resolved it or know how to correct it?

Thanks,
jr