gsub w/ field-separator

[Duran, Richard]

I've noticed what I believe to be a bug:

   echo "a b:cde:f g" | awk -F : '{gsub(/ /,"",$1);print}' -

produces "ab cde f g" instead of the expected "ab:cde:f g". It seems to be 
replacing the value of the field separator w/ a space (which I've just now 
noticed to be the default value of OFS).

The following works just fine:

   echo "a b:cde:f g" | awk -F : '{OFS=":";gsub(/ /,"",$1);print}' -

But why doesn't

   echo "a b:cde:f g" | awk -F : '{print}' -

require that OFS to be assigned a value of ":"?

(Red Hat 9 RPM: gawk-3.1.1-9)

Regards,
-richard duran