This has happened several times now intermittently over the last few
days.

D70 with SB-800 mounted and locked, both are switched on and either of
the following can happen:

SB-800 shows ISO to be 100 (a good sign that the connection isn't good
between it and the D70 - because the D70 can't do that speed). Flash
will not fire like this and sometimes the D70 won't even release the
shutter.

SB-800 goes nuts, firing itself randomly. (Happened once only)

Solution: Wiggle the flash at the shoe until it behaves.

Looks like a contact problem, but I wanted to go on record and ask if
anyone else has seen this - maybe throw some light on which device is
to blame.

--
Owamanga!