Ok, but did you record that midi using a keyboard or any kind of automation?
Here's an extract from Image-Line's support page.
Unintended automation*- Look for unintended*Event Automation*in the project. This can happen if you move any control while FL Studio is recording. Event automation is saved as a Pattern Clip and is traceable from theBrowser > Current project > Patterns*folder. Event automation will show with a knob icon and can be clicked to open the*Event Editor*so you can delete the data. Also check the*Initialized Controls Folder. Unintended initialized controls will jump to a value you are not expecting at the start of the project.