Could be that the developer is spread too thin working on Treasure of Nadia and the new game. Based on what I've read on his Patreon blog he seem to be expending an enormous amount of energy on the new game and so might not be giving Treasure of Nadia as much thought and attention as before. (Which would be a shame.) That said I still love the game and look forward to the new game whenever it gets launched.
I think NLT is too professional team to do anything they doesn't have it. I mean ToN is completed now (maybe some time back) and NLT continue in established update progress. First ToN releas was in same time to Lust Epidemic, like "New Game" to ToN. About 70%.
I love this game, but first part of game is much more interesting than now. We have here now some plot reverse, but it lacks attractiveness.
Now is all adventures and attraction on Madalyn's and Sofia's story. Yes, some girls parts are here sitll, but main relationship progress is done.