Different machine types (armv7l vs. aarch64) reported for the same HOST_ARCH (armhf)

While trying to understand why the passt package would fail to build reproducibly on armhf, I realised that in the first build, uname -a reports armv7l as machine type, and in the second one it reports aarch64, see the diff file, that is:

 I: uname -a
-  Linux virt32b 5.10.0-21-armmp-lpae #1 SMP Debian 5.10.162-1 (2023-01-21) armv7l GNU/Linux
+  Linux i-capture-the-hostname 5.10.0-21-arm64 #1 SMP Debian 5.10.162-1 (2023-01-21) aarch64 GNU/Linux

The build system of passt uses $(shell $(CC) -dumpmachine) in the Makefile to build the list of system calls allowed in seccomp profiles. On aarch64, lseek(2) is available, whereas on armv6l and armv7l, _llseek(2) has to be used. The differences in the binary output appear to come from different seccomp profiles, which are built into the executable. On armv7l, we have:

seccomp profile passt allows:  _llseek accept4 bind clock_gettime
clock_gettime64 close connect epoll_ctl epoll_pwait epoll_wait
exit_group fallocate fcntl ftruncate getsockopt listen lseek read recv
recvfrom recvmmsg recvmsg send sendmmsg sendmsg sendto setsockopt
shutdown socket timerfd_create timerfd_gettime timerfd_settime
write writev

and on aarch64:

seccomp profile passt allows:  accept4 bind clock_gettime close connect
epoll_ctl epoll_pwait epoll_wait exit_group fallocate fcntl ftruncate
getsockopt listen lseek read recvfrom recvmmsg recvmsg sendmmsg sendmsg
sendto setsockopt shutdown socket timerfd_create timerfd_gettime
timerfd_settime write writev

Should a build really be reproducible on a machine that is first reported as armhf (arm7l), and then aarch64?