Are you using a logrithmic scale? If so, then make sure that the value of one of the markers is not zero.
If not, then what version of LabVIEW are you running? Can you take your data and create a simple VI that das that data aas the default in an array and then plots it to a graph and then does the property node? This should be pretty easy to set up so that we can reproduce this issue.
Also, bug reports such as this one are normally handled better in an e-mail or phone support request.
Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask