If she is a 'J,' I don't think she's a very strong one. Or she may have registered as 'j' on the MBTI test because she might be judgmental or highly interested in a physically organized workplace.
I’m a farley strong ‘J,’ and I usually over estimate how much time it will take me to do any one activity so that I can always compensate for any hold up that I could not have foreseen (Example: if I have to drive over a two mile stretch of road and I have no idea if there’s going to be traffic, I’ll just mentally calculate how much time it would take if I were driving that two mile stretch at five miles an hour. Something like twenty four minutes.)
To be honest, this is the first I’ve heard of an INTJ being consistently unpunctual.
How strong of a J is she? And if she is an extremely strong J, that begs the question: “are there different types of J’s?”