From what I have seen of those that I extracted from the DHP: most of them are wrong! You can see in this specific example that the reference is to Kv 2.4 Aṭṭhamavagga/ Kāmakathā - the second part of the reference is correct but the number is wrong. This is something I have seen in the DHP very often too. Like you said, this is a systematic error.
I will write a little python program to extract them all into one file, but still they would need to be gone over by hand (maybe ask for a volunteer?) and then added to the JSON database I am working on.
I C. I will make this an issue on Github and can renumber them using the python tool for that. But this will also have an effect on all parallels and cross references referring to those.
(PS. Not sure if this issue should be here - which is the post for adding new parallels)