Update.
So I just chang the line.
#define portASPEN_AND_LSPEN_BITS ( 0x1UL << 31UL )
After making this adjustment, I ran my project and used the register viewer to check the registers. Lazy Stacking is disabled, but somehow the same problem persists.
I think perhaps the data in registers s0-s15 is not being saved in the task stack? In port.asm, it only deals with registers s16-s31 and the FPU driver deals with s0-s15.