Add another check for "no price/size" empty values

Also adds some historical debug details for trying to figure out why the
IBKR APIs return bad SPX values after hours (it always does this and
even their official apps/sites report the bad values).

As far as I can tell, there's a bug in the IBKR data APIs where, after
hours, it returns the _correct_ value followed immediately by some
incorrect value (maybe it's adjusted for something?) but we can't seem
to capture the "good value" before the bad value replaces it because
there's no indicator which value is which (other than the order they
arrive in immediately when connecting).