Is there a story behind this: “As a reminder to all trainers, it is both inadvisable and irresponsible to reignite your cyndaquil by feeding it coffee. If your cyndaquil’s fire goes out, allow it to sleep.” That just seems like something said from personal experience or a story passed around at family gatherings.

There is indeed a story, anonymous. That story is: “I have lost count of how many times there have been incidents in Johto of people doing exactly this.” They did a special on it in the 90s, alongside an entire campaign about it. “Friends don’t let friends feed their cyndaquil coffee” and “just say no to coffee” and so forth.