PerlMonks really never deletes nodes. But not to worry; we all have asked questions that have been based on mistaken assumptions. It happens, nobody's judging (or they shouldn't be). And the thread still has value, as it demonstrates HERE doc interpolation, and a debugging technique.
Truth be told, I expected that the result of boiling your bug down to a sample snippet would lead you to your answer. I thank you for having taken the time to do that, and am glad that it did help resolve the problem. Whenever I encounter something that makes me think Perl's not behaving as expected I try to practice that same strategy; write a one-liner, or a small (fewer than 25 lines) script that demonstrates the problem. And more often than not I won't even finish typing it before I have the ah-hah moment. It's tremendously unlikely that Perl's HERE docs have a bug in how they handle interpolation that is so glaring that one instance of interpolation would fail to happen. I don't know how many times I've thought to myself, "That shouldn't be happening, I'll pull it into an example snippet so I can play with it." And then presto, the issue turns up.