This has previously been reported.
For More Information see: FMPA14 Script step line jumping
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip
Thank you for your post.
As PhilModJunk pointed out (Thank you!), this issue has been previously reported, and our Development and Testing teams are aware of this issue. I have attached your post to the original report. When more information becomes available, I will post again.