I came across this little oddity using DBPro patch 4 (not sure if its just a patch 4 thing or not).
In the code below I define a simple type, then create 2 variables of that type, the first variable I give a value to, the other I don`t, then I compare them.
Oddly they appear to be neither equal nor not equal. If you add in the commented out line, which sets the second type to an empty string, it works OK.
I suspect the unset type might have an 'UNSET' value (like NULL in a Database) which does not work with comparisons, anyway the rule is 'ALWAYS EXPLICITLY SET VALUES IN TYPES BEFORE DOING COMPARISONS'.
"Don`t try to engage my enthusiasm, I don`t have one"