add detect bad tcp options ?

I received this packet,
but bro not detect bad tcp options,
possible pb on bro ?
because 'bad tcp cksum' ?

If the TCP checksum is bad, then the packet is ill-formed. It does not
make sense in that case to complain about a bad option, since the packet
cannot be processed in any case.

why bro detect OTH ?

Because the connection is not in a well-defined state. Bro does *not*
consider it to have corresponded to a SYN being sent, because the packet
carrying the SYN was ill-formed. For all it can tell, part of the damage
to the packet might have been to the control flags, and the SYN setting
is bogus.