FCPX: Retime toggle options, “speed transitions” and “preserve pitch” are greyed out. Why?

In the dropdown retime menu of the viewer there are toggle option tick boxes for “speed transitions” and “preserve pitch.” I have been keeping the “speed transitions” unticked and using the range tool to quickly select and 2X the speed of timeline ranges within clips. Suddenly, both options, “speed transitions” and “preserve pitch” are greyed out and default ticked for a new clip I’m working on. The clip seems identical to the previous ones in every way, both are compound clips. Now every time I apply a 2X retime using the range tool I get start and end speed ramps, which I do not want. if I go back to work on the old clips the options are no longer greyed. So it is clip dependent. What has changed to grey out these options?