Have you solved it yet? We had the same crash problem you had:
Crashed: com.apple.network.connections
0 libxpc.dylib 0x15bfc _xpc_dictionary_insert + 96
1 libxpc.dylib 0x177a8 _xpc_dictionary_copy_apply + 76
2 libxpc.dylib 0x15248 _xpc_dictionary_apply_node_f + 156
3 libxpc.dylib 0x144c4 _xpc_dictionary_copy + 88
4 Network 0x27e174 -[NWConcrete_nw_protocol_options initWithOptions:] + 184
5 Network 0x323240 __nw_protocol_stack_copy_block_invoke_2 + 64
6 Network 0x7065c4 nw_array_apply + 124
7 Network 0x322dcc nw_protocol_stack_copy + 308
8 Network 0x32a310 -[NWConcrete_nw_parameters initWithParameters:stripConnected:shallowCopy:] + 592
9 Network 0x47993c nw_endpoint_resolver_create_child_parameters + 116
10 Network 0x4784e8 nw_endpoint_resolver_update + 5920
11 Network 0x481f68 __52-[NWConcrete_nw_endpoint_resolver startWithHandler:]_block_invoke_2 + 84
12 Network 0x144e08 __nw_resolver_update_client_block_invoke + 88
13 libdispatch.dylib 0x24b4 _dispatch_call_block_and_release + 32
14 libdispatch.dylib 0x3fdc _dispatch_client_callout + 20
15 libdispatch.dylib 0xd620 _dispatch_workloop_invoke + 2076
16 libdispatch.dylib 0x16e10 _dispatch_workloop_worker_thread + 652
17 libsystem_pthread.dylib 0xdf8 _pthread_wqthread + 288
18 libsystem_pthread.dylib 0xb98 start_wqthread + 8