So maybe my opinion doesn't count.. But as a writer, I can see where you're coming from. I don't post serials unless it longer than 30K word and then the first chapter doesn't go up until the last chapter and maybe the epilogue is finished.

But in the writing it's not uncommon for me to have two or more works in progress. I write in two genres; TG and another that I want to keep separate and I use a different pen name. I currently have four WIP in the other genre and four in TG I'm actively working on; plus four in TG that I intend to get back too one of these days.

There are lots of reasons to jump around like that. My main reason it that I come to a place in the story line where I know where it needs to go, but can't seem to string the words together to get it there. Another is the story arc is just too intense to stay in it and I need to let my emotions calm down so that the story flows graciously. The most annoying reason is that my muse has ADD/ADHD and just can't stay on task; in the middle of a good part she gives me an idea for another story and won't leave me alone about it until start on it.

In short do what you need to do to keep the creative juices flowing.