Look, there are no hard rules on chapter lengths...it's more about what's in 'fashion'. Shorter chapters are in vogue right now....say 1500 to 2000 words. I don't know whether that's a reflection on the short attention span of readers today, or because of reading habits (ie: we do most of our reading on buses and trains)...and hence only have shorter periods in which to ingest our books. And this of course varies from genre to genre....thrillers, YA, ChikLit tend to have shorter, pacier chapters...whilst historical fiction, literary stuff, tend to be longer.
I have noticed in many published books, chapters being 'broken up' in very arbitrary ways. Clearly in these books, some of these chapters were grouped together as one, but I'm guessing an editor has said that some of the chapters are too long, and the author has simply snapped them in two without being clever about rounding the first off with a cliffhanger etc etc. And you know what?...it doesn't really matter. I mean...you don't want a chapter break mid sentence, or halfway through describing something, but where you might start a new paragraph might suit as a chapter break. It's certainly something not to agonize over too long and hard.
For my novel, I had to break up some chapters that had swollen out of proportion with all the other chapters...in particular, an action sequence that had grown to about 7k words. It was easy enough, to wait for a lull in the action as both sides reloaded, and call that the chapter break. It worked just fine!