I'm a combination plotter and panster. I come up with a basic plot and list of characters for my stories, but the scenes often take a different path than I envisioned when I actually write them. Character's come to life and flesh themselves out as I type. It's kind of neat to watch.
Of course, I have to be flexible. When I start writing a particular
interaction, I sometimes realize a line of dialogue or character
reaction is implausible and have to change course. At other times, the
research alters something about the scene or a character's backstory.
It's fun and interesting at times, frustrating at others.
With my historicals, a lot of research is done during the plotting stage, and more is necessary during drafting. I'm constantly fact-checking. Many times something I learn from a non-fiction source gives me the idea for an entire scene. Heck, some of my best scenes were inspired by research. But it usually doesn't change anything too significant.
This time is different.
The current novel I'm working on has been sucking in historical topics I never saw coming. I had to go back and change details so my heroine could have the proper wardrobe. What I discovered when I looked up a 19th-century church, simply to get the location and building details right, changed a character's backstory drastically and gave rise to unplanned scenes. Supporting characters who were only supposed to appear in a chapter or two are sticking around and showing back up. I'm sure the story will be better for it, but good grief! My head is swimming!
Does this ever happen to you when you write?