Bangle2: incorrect time after weekend

Just experienced the frozen watch again:

• After switching from webIDE(pc) to GB(phone), the clock stopped updating. (no reaction to tap, twist, button,...)
  
• No "find my watch", no messages could trigger anything, but still GB showed a connected watch. Even after some minutes.
  
• After disconnecting in GB -> still nothing.
  
• After reconnecting in GB -> everything back to normal.