I have not reproduced such problem on HW and I think your project works properly therefore it is probably HW issue. Since you have enabled the PLL clock in your project, you should check the connection of the filter on pin 3.
More information about filter connection can be found in chapter "5.3.9 CGM External Connections" in
MC68HC908GP32 datasheet.
best regards
Vojtech Filip
Processor Expert Support Team
UNIS