Why does perf+coresight print leading hexits of addresses with 'a'?

I compile coresight and perf on my dragonboard 410c.

I have disabled user address space randomization.

I run my application program under perf, and then run `perf script`.

The address perf+opencoresight prints for main is: aaaaaaaaa910 main+0x0 (nm on the application program says the address for main is 0x910).

Why does perf+coresight change the leading hexits in the printed address from 0 to 'a'?

Is there a way to disable this behavior?

Is this behavior documented anywhere?

Many thanks, Robert Henry