Motion generator moves too fast after being published into fcp

I created a generator in Motion (v5.8), which is like a moving paper textual background. I applied 'strobe' behaviour to control the moving speed of this background. I published 'strobe rate' to fcp. And I added a marker to indicate the project loop end. Then i published this into fcp (v10.8.1) as a generator.

But when I drag this generator to the timeline in fcp, it simply moves too fast - just like there is no 'strobe' behaviour applied. The 'strobe rate' in Motion is '5', and it looks perfect. But when the 'strobe rate' shows '5' in fcp, it moves so fast, completely different from what it looks like in Motion.

I checked the frame rate - the generator Motion project is 24 fps and my fcp project is 24 fps as well. I really don't know what went wrong.

It will be highly appreciated if someone could help!