Just a guess, but often politics is less about what gets done than it is about who gets to claim credit. Stalling until the next Congress could be someone either trying to take credit or offload blame, possibly not even the person or party seeming like the obstacle, since they trade favors. It could even be something as simple as being able to claim bipartisanship after the switch.

“We have been working on this bill in order to advance it, including working with DOJ and stakeholders to address issues with the language,” a Judiciary Committee aide said.

https://www.huffingtonpost.com/entry/native-women-abused-bil...

No idea at all. A sibling comment notes there some mushy statements about working with the DOJ. It's very, very hard to believe that Rep. Goodlatte is unique in his cares or communications with the DOJ about the impact of the bill. Occams razor points to something pettier.

In any case, he's on his way out.