DC and Nyquist values are higher than all other bins
For a mean centered (DC removed, pure AC) signal the first bin of the FFT output should be an exact zero. In your plot, this zero output sample is possibly obscured by the squeezing of the graph display; i.e., if you zoom into the left side of your plot, you should see that zero valued first bin sample...

Furthermore, for a typical FFT computation of real data, the second half of the FFT bins, is a conjugate symmetric mirror of the first half (excluding the DC and / or the Nyquist bins). Note that the Nyquist bin is (about) at the center of the FFT output, and to the right of this Nyquist bin is the mirrored content. Note also that exact Nyquist frequency bin exists only for even length FFTs and not for odd length FFTs.

Looking into your output, the last and the first bins seem like mirrors; but that's wrong as I have indicated, your fist FFT bin must be a zero, and even if it's not zero, it won't be mirrored to the last bin. What's mirrored to the last bin is actually the second bin of the FFT output.