Ah, no worries... it's just that "bug" is kind of a loaded, and often misused term.
In my modding work, I only use the term bug when 1) I find something totally unexpected and counter-intuitive (from an engineering standpoint) while I'm in the middle of trying to add/fix a feature that really doesn't need any more complications 2) I run into non-optimal behavior in the software that I can't get around using the tools at my disposal.
So, the lack of the TB-23 on the 688i in the stock game: NOT a bug. The improper ascent of the submarines to PD: definately a bug.
But that's only from my perspective.
Cheers,
David