BOLT flashing strangely

One of my Sphero BOLTs flashes strangely sometimes, it’s in the charging dock (which is flashing blue per usual), but sometimes the BOLT will flash all sorts of colors very quickly from red, orange, yellow, green, really quick. And sometimes only one LED will light up red. Other times, the BOLT won’t flash anything. What is the cause of this? This is my first time using this BOLT, though I have had it for around a month.

It does not “turn on” like my other BOLT does when I tap it after removing it from the charging dock. The BOLT is visible through SpheroEDU but cannot be connected to.