All track data sources will suffer this to some extent or other. I have used CNIG, OSM, Wise Pilgrim and the Dutch Pilgrim Association tracks over the years. None of them have been consistently perfect. Wise Pilgrim and
Brierley (if you use his guides) have the advantage of getting feedback from pilgrims on the ground. Wise Pilgrim has turned comments I have made around in a couple of days or less. Clearly not something that the publishers of
Brierley can do with a printed guide.
Even with good track information, when you are walking, you still need to pay attention to the waymarking. It doesn't pay to walk mindlessly following a GPS track as your only reference. There are not many times where I have been confused where the current way-marking has indicated a different path to the GPS track I have been using, but I am always going to make sure that I understand why that might be before keeping going.