Dropped a 430EX (Mk1) about 3-4 ft from a light stand onto grass at the start of a gig. Not even a scuff mark and seems to work fine but when I pull out the wide diffuser the LCD text flashes. I can set the manual power. Zoom shows 14mm. Is this normal operation? Zoom works when I put the wide angle screen back in. I hardly ever use the screen and the manual doesn't mention this.