Double-free in some signal emit

I'm not exactly sure what I did to trigger this, but it was while debugging the keyboard:

Invalid write of size 8
  in wl_list_insert in /usr/lib64/libwayland-server.so.0.1.0
  1: wl_list_insert in /usr/lib64/libwayland-server.so.0.1.0
  2: wlr_signal_emit_safe in /home/.rhn_slow/work/purism/osk/phoc/subprojects/wlroots/util/signal.c:19
  3: ffi_call_unix64 in /usr/lib64/libffi.so.6.0.2
  4: ffi_call in /usr/lib64/libffi.so.6.0.2
  5: /usr/lib64/libwayland-server.so.0.1.0
  6: /usr/lib64/libwayland-server.so.0.1.0
  7: wl_event_loop_dispatch in /usr/lib64/libwayland-server.so.0.1.0
  8: wayland_event_source_dispatch in /home/.rhn_slow/work/purism/osk/phoc/src/server.c:42
  9: g_main_dispatch in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3182
  10: g_main_context_dispatch in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3847
  11: g_main_context_iterate.isra.21 in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3920
  12: g_main_loop_run in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:4116
  13: main in /home/.rhn_slow/work/purism/osk/phoc/src/main.c:96
Address 0x8658810 is 224 bytes inside a block of size 256 free'd  1: free in /builddir/build/BUILD/valgrind-3.15.0/coregrind/m_replacemalloc/vg_replace_malloc.c:540
  2: text_input_handle_seat_destroy in /home/.rhn_slow/work/purism/osk/phoc/subprojects/wlroots/types/wlr_text_input_v3.c:221
  3: wlr_signal_emit_safe in /home/.rhn_slow/work/purism/osk/phoc/subprojects/wlroots/util/signal.c:29
  4: seat_client_handle_resource_destroy in /home/.rhn_slow/work/purism/osk/phoc/subprojects/wlroots/types/seat/wlr_seat.c:69
  5: /usr/lib64/libwayland-server.so.0.1.0
  6: /usr/lib64/libwayland-server.so.0.1.0
  7: /usr/lib64/libwayland-server.so.0.1.0
  8: wl_client_destroy in /usr/lib64/libwayland-server.so.0.1.0
  9: /usr/lib64/libwayland-server.so.0.1.0
  10: wl_event_loop_dispatch in /usr/lib64/libwayland-server.so.0.1.0
  11: wayland_event_source_dispatch in /home/.rhn_slow/work/purism/osk/phoc/src/server.c:42
  12: g_main_dispatch in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3182
  13: g_main_context_dispatch in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3847
  14: g_main_context_iterate.isra.21 in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3920
  15: g_main_loop_run in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:4116
  16: main in /home/.rhn_slow/work/purism/osk/phoc/src/main.c:96
Block was alloc'd at  1: calloc in /builddir/build/BUILD/valgrind-3.15.0/coregrind/m_replacemalloc/vg_replace_malloc.c:762
  2: text_input_manager_get_text_input in /home/.rhn_slow/work/purism/osk/phoc/subprojects/wlroots/types/wlr_text_input_v3.c:235
  3: ffi_call_unix64 in /usr/lib64/libffi.so.6.0.2
  4: ffi_call in /usr/lib64/libffi.so.6.0.2
  5: /usr/lib64/libwayland-server.so.0.1.0
  6: /usr/lib64/libwayland-server.so.0.1.0
  7: wl_event_loop_dispatch in /usr/lib64/libwayland-server.so.0.1.0
  8: wayland_event_source_dispatch in /home/.rhn_slow/work/purism/osk/phoc/src/server.c:42
  9: g_main_dispatch in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3182
  10: g_main_context_dispatch in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3847
  11: g_main_context_iterate.isra.21 in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:3920
  12: g_main_loop_run in /usr/src/debug/glib2-2.58.3-1.fc29.x86_64/glib/gmain.c:4116
  13: main in /home/.rhn_slow/work/purism/osk/phoc/src/main.c:96