I also have two IQ338XL. And I also have one of the newer ones that blink when finished - and one that doesn't. The note (one of the left) says "display flashes when done, this one only".
I've never noticed a problem with reading the display though. That being said, the blinking can be annoying in the middle of the night. I used to place something over the display for that. It bothered my wife more than me.
The first one was purchased through Amazon Sept 2017, the second one (that blinks) Oct 2017, also through Amazon.
