I just posted this on the list serve less than an hour ago:

'67 does have a safety catch, but it can fail if the catch spring
fails or if it sticks. I believe the '68-69 latch and hood catch work
together to mechanically force the safety catch closed if the hood
pops off the primary latch. Perhaps there is something wrong with
your '67 latch or perhaps it's not adjusted well enough. I would
definitely take a look at it.