Seccomp: sandbox crash on rt_sigaction with libseccomp 0.2.4

With Sandbox=1 I do get with the new stable Vanilla Linux kernel

============================================================ T= 1553016509
(Sandbox) Caught a bad syscall attempt (syscall rt_sigaction)
/usr/bin/tor(+0x1ce5aa)[0x5636adfa15aa]
/lib64/libpthread.so.0(+0x14125)[0x7f0d99074125]
/lib64/libpthread.so.0(+0x14125)[0x7f0d99074125]
/usr/lib64/libevent-2.1.so.6(evsig_set_handler_+0xeb)[0x7f0d99f4df8b]
/usr/lib64/libevent-2.1.so.6(+0x2c0b6)[0x7f0d99f4e0b6]
/usr/lib64/libevent-2.1.so.6(evmap_signal_add_+0xb5)[0x7f0d99f46b55]
/usr/lib64/libevent-2.1.so.6(event_add_nolock_+0x74e)[0x7f0d99f421ce]
/usr/lib64/libevent-2.1.so.6(event_add+0x3a)[0x7f0d99f423fa]
/usr/bin/tor(handle_signals+0xa7)[0x5636ade2a0c7]
/usr/bin/tor(run_tor_main_loop+0x1a)[0x5636ade2ac8a]
/usr/bin/tor(tor_run_main+0x1045)[0x5636ade2bea5]
/usr/bin/tor(tor_main+0x43)[0x5636ade293e3]
/usr/bin/tor(main+0x19)[0x5636ade28f99]
/lib64/libc.so.6(__libc_start_main+0xe7)[0x7f0d98cb9ae7]
/usr/bin/tor(_start+0x2a)[0x5636ade28fea]

An strace narrows it down to

write(2, "(Sandbox) Caught a bad syscall a"..., 48(Sandbox) Caught a bad syscall attempt (syscall ) = 48