disable_sescmd_history causes MaxScale to crash under load

When I throttle the queries like here:

( for i in `seq 1 100000`; do echo "set @test=$i;"; sleep 0.1; done ) | mysql -h 10.3.1.110 -utpcc -ptpcc tpcc

MaxScale is stable and memory is stable. But if I remove the sleep, it quickly crashes and in the trace, I found it is always when the following message appears:

2015-05-06 10:57:25 [3] Backend 172.30.1.102:3306 already executing sescmd

Usually after just 4 or 5 statements.

From the backtrace,

2015-05-06 10:57:25 Fatal: MaxScale received fatal signal 11. Attempting backtrace.
2015-05-06 10:57:25 ./bin/maxscale() [0x54cb98]
2015-05-06 10:57:25 /lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0) [0x7fb5b4036cb0]
2015-05-06 10:57:25 /usr/local/mariadb-maxscale/modules/libreadwritesplit.so(+0xa16d) [0x7fb59830116d]
2015-05-06 10:57:25 /usr/local/mariadb-maxscale/modules/libreadwritesplit.so(+0x8544) [0x7fb5982ff544]
2015-05-06 10:57:25 /usr/local/mariadb-maxscale/modules/libMySQLBackend.so(+0x4ee8) [0x7fb595ea9ee8]
2015-05-06 10:57:25 ./bin/maxscale() [0x55f874]

The issue seems to be at the beginning of sescmd_cursor_process_replies, if I am correct:

static GWBUF* sescmd_cursor_process_replies(
GWBUF* replybuf,
backend_ref_t* bref,
bool *reconnect)
{
mysql_sescmd_t* scmd;
sescmd_cursor_t* scur;
ROUTER_CLIENT_SES* ses;
ROUTER_INSTANCE* router;

scur = &bref->bref_sescmd_cur;
ss_dassert(SPINLOCK_IS_LOCKED(&(scur->scmd_cur_rses->rses_lock)));
scmd = sescmd_cursor_get_command(scur);
ses = (*scur->scmd_cur_ptr_property)->rses_prop_rsession;
router = ses->router; <----- here

Looks like something isn't protected when the properties are removed.