(lldb) bt
* thread #1, name = 'python', stop reason = signal SIGABRT
  * frame #0: 0x00007ffff7a22e97 libc.so.6`__GI_raise(sig=2) at raise.c:51
    frame #1: 0x00007ffff7a24801 libc.so.6`__GI_abort at abort.c:79
    frame #2: 0x00007ffff58b5f1f libwiredtiger-3.2.2.so`__wt_abort(session=0x0000555555dca748) at os_abort.c:30
    frame #3: 0x00007ffff57e5114 libwiredtiger-3.2.2.so`__wt_find_lookaside_upd(session=0x0000555555dca748, cbt=0x0000555555e94440, updp=0x00007fffffffc3e8, allow_prepare=false) at cache_las.c:1266
    frame #4: 0x00007ffff5759430 libwiredtiger-3.2.2.so`__wt_txn_read(session=0x0000555555dca748, cbt=0x0000555555e94440, upd=0x0000555555ec0fd0, updp=0x00007fffffffc498) at txn.i:837
    frame #5: 0x00007ffff5758147 libwiredtiger-3.2.2.so`__cursor_row_next(cbt=0x0000555555e94440, newpage=true, restart=false) at bt_curnext.c:388
    frame #6: 0x00007ffff5756bf5 libwiredtiger-3.2.2.so`__wt_btcur_next(cbt=0x0000555555e94440, truncating=false) at bt_curnext.c:659
    frame #7: 0x00007ffff5828de8 libwiredtiger-3.2.2.so`__curfile_next(cursor=0x0000555555e94440) at cur_file.c:92
    frame #8: 0x00007ffff5bd2d2d _wiredtiger.so`_wrap_Cursor_next(self=<unavailable>, args=<unavailable>) at wiredtiger_wrap.c:4161
    frame #9: 0x0000555555650724 python`PyEval_EvalFrameEx + 31188
    frame #10: 0x000055555564d8cd python`PyEval_EvalFrameEx + 19325
    frame #11: 0x0000555555646b0a python`PyEval_EvalCodeEx + 1754
    frame #12: 0x00005555556620b9 python`___lldb_unnamed_symbol3296$$python + 73
    frame #13: 0x000055555567a3ae python`___lldb_unnamed_symbol3409$$python + 414
    frame #14: 0x00005555556322ae python`PyObject_Call + 62
    frame #15: 0x00005555556ec716 python`___lldb_unnamed_symbol4213$$python + 70
    frame #16: 0x0000555555649812 python`PyEval_EvalFrameEx + 2754
    frame #17: 0x000055555564d8cd python`PyEval_EvalFrameEx + 19325
    frame #18: 0x000055555564d8cd python`PyEval_EvalFrameEx + 19325
    frame #19: 0x0000555555646b0a python`PyEval_EvalCodeEx + 1754
    frame #20: 0x000055555566235c python`___lldb_unnamed_symbol3296$$python + 748
    frame #21: 0x00005555556322ae python`PyObject_Call + 62
    frame #22: 0x000055555564b4f3 python`PyEval_EvalFrameEx + 10147
    frame #23: 0x0000555555646b0a python`PyEval_EvalCodeEx + 1754
    frame #24: 0x00005555556620b9 python`___lldb_unnamed_symbol3296$$python + 73
    frame #25: 0x000055555567a3ae python`___lldb_unnamed_symbol3409$$python + 414
    frame #26: 0x00005555556322ae python`PyObject_Call + 62
    frame #27: 0x00005555556d6953 python`___lldb_unnamed_symbol3982$$python + 51
    frame #28: 0x000055555564df9e python`PyEval_EvalFrameEx + 21070
    frame #29: 0x0000555555646b0a python`PyEval_EvalCodeEx + 1754
    frame #30: 0x000055555566235c python`___lldb_unnamed_symbol3296$$python + 748
    frame #31: 0x00005555556322ae python`PyObject_Call + 62
    frame #32: 0x000055555564b4f3 python`PyEval_EvalFrameEx + 10147
    frame #33: 0x0000555555646b0a python`PyEval_EvalCodeEx + 1754
    frame #34: 0x00005555556620b9 python`___lldb_unnamed_symbol3296$$python + 73
    frame #35: 0x000055555567a3ae python`___lldb_unnamed_symbol3409$$python + 414
    frame #36: 0x00005555556322ae python`PyObject_Call + 62
    frame #37: 0x00005555556d6953 python`___lldb_unnamed_symbol3982$$python + 51
    frame #38: 0x000055555564df9e python`PyEval_EvalFrameEx + 21070
    frame #39: 0x000055555564d8cd python`PyEval_EvalFrameEx + 19325
    frame #40: 0x0000555555646b0a python`PyEval_EvalCodeEx + 1754
    frame #41: 0x000055555564e77a python`PyEval_EvalFrameEx + 23082
    frame #42: 0x0000555555646b0a python`PyEval_EvalCodeEx + 1754
    frame #43: 0x0000555555646429 python`PyEval_EvalCode + 25
    frame #44: 0x00005555556764cf python`___lldb_unnamed_symbol3389$$python + 47
    frame #45: 0x0000555555671442 python`PyRun_FileExFlags + 130
    frame #46: 0x00005555556708bd python`PyRun_SimpleFileExFlags + 397
    frame #47: 0x000055555562075b python`Py_Main + 1675
    frame #48: 0x00007ffff7a05b97 libc.so.6`__libc_start_main(main=(python`main), argc=3, argv=0x00007fffffffe4e8, init=<unavailable>, fini=<unavailable>, rtld_fini=<unavailable>, stack_end=0x00007fffffffe4d8) at libc-start.c:310
    frame #49: 0x000055555561ffda python`_start + 42
(lldb) frame select 3
frame #3: 0x00007ffff57e5114 libwiredtiger-3.2.2.so`__wt_find_lookaside_upd(session=0x0000555555dca748, cbt=0x0000555555e94440, updp=0x00007fffffffc3e8, allow_prepare=false) at cache_las.c:1266
   1263	     * Prior to calling this function, we should have successfully searched the correct key with our
   1264	     * cursor.
   1265	     */
-> 1266	    WT_ASSERT(session, cbt->compare == 0);
   1267
   1268	    /* Row-store has the key available, create the column-store key on demand. */
   1269	    switch (cbt->btree->type) {