Memory problem on DL580 G7 512Gb

Hi.

We have some problem with memory on DL580G7.

After suddenly fail our server lose about 32Gb memory.

Our configuration is 8 memory riser x 8x8Gb on each and must be 512Gb.

So we have try mix,remap memory bank,risers. No error,no fail bank. But show only 480Gb memory available.

I attached screenshot of memery test. There writen 491520Mb Available  and 524288 Mb Configured.

What we missed or what we can do in this situation?
tnx