bug in sstp in 6.40.2

After updating router os from 6.39 to 6.40.2 getting this bug.
I have a ppoe connection to obtain internet access and then connecting an sstp vpn for remote access.
After updating to 6.40.2 SSTP connection goes online and offline,connected and dissconected, lots and lots, about every 5 seconds but in 6.39 , no problem.
Just reporting the bug. Please fix it asap

for any investigation,export of ppp interfaces and default routes is:

/interface pppoe-client
add add-default-route=yes default-route-distance=10 disabled=no interface=\
    ether1 keepalive-timeout=disabled name=pppoe-out1 password=somepasss \
    user=someuser
    /ppp profile
add change-tcp-mss=no name=profile1 use-compression=no use-encryption=required \
    use-ipv6=no use-mpls=no use-upnp=no
/interface sstp-client
add add-default-route=yes connect-to=someserver.net disabled=no \
    name=sstp-out1 password=somepass profile=default-encryption user=someuser\
    verify-server-address-from-certificate=no