circuit_pick_extend_handshake: Non-fatal assertion !(node_prev == NULL) failed

Oct 26 16:32:51.000 [warn] tor_bug_occurred_: Bug: src/or/circuitbuild.c:859: circuit_pick_extend_handshake: Non-fatal assertion !(node_prev == NULL) failed. (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug: Non-fatal assertion !(node_prev == NULL) failed in circuit_pick_extend_handshake at src/or/circuitbuild.c:859. Stack trace: (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     0   tor                                 0x000000010b4d8f00 log_backtrace + 64 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     1   tor                                 0x000000010b586906 tor_bug_occurred_ + 790 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     2   tor                                 0x000000010ad024f3 circuit_pick_extend_handshake + 435 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     3   tor                                 0x000000010acfbf6a circuit_send_next_onion_skin + 12362 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     4   tor                                 0x000000010ad0b99f circuit_extend_to_new_exit + 335 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     5   tor                                 0x000000010b2dcd0a rend_client_reextend_intro_circuit + 1450 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     6   tor                                 0x000000010b2df3dc rend_client_introduction_acked + 5276 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     7   tor                                 0x000000010b2f8848 rend_process_relay_cell + 1464 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     8   tor                                 0x000000010b2a3fe2 connection_edge_process_relay_cell + 37938 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     9   tor                                 0x000000010b2960ce circuit_receive_relay_cell + 2798 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     10  tor                                 0x000000010add98a0 command_process_relay_cell + 5488 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     11  tor                                 0x000000010add38f9 command_process_cell + 409 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     12  tor                                 0x000000010ac7e89f channel_queue_cell + 2447 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     13  tor                                 0x000000010ac9f3a3 channel_tls_handle_cell + 4099 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     14  tor                                 0x000000010af2af62 connection_or_process_cells_from_inbuf + 3170 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     15  tor                                 0x000000010af2881e connection_or_process_inbuf + 1454 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     16  tor                                 0x000000010aed2e9b connection_process_inbuf + 427 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     17  tor                                 0x000000010aeafc19 connection_handle_read_impl + 7033 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     18  tor                                 0x000000010aeae068 connection_handle_read + 40 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     19  tor                                 0x000000010b15eb2a conn_read_callback + 490 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     20  tor                                 0x000000010b6c71a6 event_base_loop + 1858 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     21  tor                                 0x000000010b181819 run_main_loop_once + 1433 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     22  tor                                 0x000000010b16bb62 run_main_loop_until_done + 34 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     23  tor                                 0x000000010b168f58 do_main_loop + 4504 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     24  tor                                 0x000000010b16f0ac tor_main + 1132 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     25  tor                                 0x000000010ac269d0 main + 48 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     26  libdyld.dylib                       0x00007fff9d8c65ad start + 1 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)
Oct 26 16:32:51.000 [warn] Bug:     27  ???                                 0x000000000000000f 0x0 + 15 (on Tor 0.2.9.3-alpha-dev 153ff4f559d9b7ee)