Use only short discrete clips for remapping. A subclip remapped from a master clip that is captured from an entire tape roll never seems to work right. Export the single clip then reimport and remap it.
Personally, I log and capture all of my clips to avoid troubles like this. I’m not a fan of capturing entire rolls then subclipping them even though it saves time in the short run. Anomolies occur with speed, time remapping, reconnecting and media management. These are troubles I don’t really like to deal with, so I log and capture the old fashioned way. Takes longer but is an inherently more stable way to work with FCP.
Kevin Monahan
Author – Motion Graphics and Effects in Final Cut Pro
fcpworld.com