The first path does not correspond to the CIR data

Wireless Connectivity Ultra-Wideband
1

I’m using dwm1001 to collect CIR data by using dwt_readaccdata(), and get first path data by
dwt_readfromdevice(0x15, 5, 2, reg);
fp = reg[0];
fp = fp + (reg[1] << 8);
fpath = (double)fp * (1.0 / 64.0);

Then I align the CIR data according to first path. However, I found the first path does not correspond to the CIR data， which make multiple CIR data difficult to align, like this figure.

figure
figure1415×681 230 KB

Can you suggest some way , How I can solve this problem?

Thanks & Regards,
Rock