Why would I imagine that? This kind of thing happens from time to time with gas cars. Example (picked lazily and randomly): https://www.cbsnews.com/newyork/video/car-erupts-in-flames-n...
In some respects, Lithium Ion fires are harder to manage, but they also seem to happen less frequently.
Maybe don't jump to conclusions based upon ~10 fires in vehicles flooded by saltwater?