I have checked this and it seems that bldc_ref_sol.pmp project file in MCRSP_BLDC_V1.3.0 is configured to check for missing symbols even after the FreeMASTER project opening.
All the sensorless BLDC control SW examples are using FreeMASTER Target-Side Addressing (TSA) so all symbols (addresses, names, and sizes of selected variables within MCU) are loaded when the communication with the target MCU is established (you must do this manually by clicking green GO! button - see more details in users guide). You can read more about the FreeMASTER TSA here: https://www.nxp.com/docs/en/user-guide/FMSTRSCIDRVUG.pdf
Therefore, the Missing Symbol Definition dialog window after opening the pmp file has no significance (the target MCU is not connected at that time).
If you want, then there is a simple way to disable this warning in FreeMASTER 3.0. After opening the bldc_ref_sol.pmp project file, do the following:
Go Project→Options... or press Ctrl+T.
In the Options window, go to MAP Files tab.
Select the Except after project load option for On Load List Errors setting.
Save the changes to the FreeMASTER project file.
Close the pmp file and open it again - the warning should be gone.