LVT installers opinions?

We were looking to have latex screeding put down and then glue down LVT installed. We have just found these cracks under the old laminate that was here when we moved in. Is there anyone who installs LVT / knows it well to advise what would need to be done to these cracks before doing the latex / installation? Worried about having it all done and if it were to just happen again. Thanks for any help