When I was tracking in mocha pro, at some point some previous frames repeats and tracking getd out of range. The frame after this will be continuation of the original clip, but sometimes some frames repeat
Are you using the plugin or the standalone? And if so, what version? Do you potentially have doubled up frames in the clip? Or, are you using a movie file, if you are using a movie file, what is the codec?
I need more information to help you diagnose this issue.