What does flashing red vs solid red mean on a Blendjet?

i had one that flashed red and turned out the button itself was stuck halfway pressed. Cleaned around it with isopropyl and it was fine. Seperate issue from the battery entirely
 
i had one that flashed red and turned out the button itself was stuck halfway pressed. Cleaned around it with isopropyl and it was fine. Seperate issue from the battery entirely

That's actually a really common one. Smoothie residue gets under the button membrane and it reads as a constant press, then the controller throw an error because it thinks you're trying to start it without a cup.