I have been updating my Pixy2 demo for a couple hours today when -- as I was contemplating how to make things better -- I watched all of the blocks get erased from the screen. Gone. All of them. I closed the browser without saving, hoping that this would preserve my last save, even if I did lose a few changes. Thankfully, it did.
That said, when I did a test compile there were a bunch of errors leading back to the serial object. I've been experiencing this a lot, but finally reporting it. My serial object is using pins 5 and 4, hence gets named fdser5_4. When the errors occur, I notice that the reference to this object are called fdser0_0. Clearly, there is a problem in the blocks to code translation, but it is not consistent.