As has been documented (here and here for example), the 15c LE display will flash oddly in various situations. I discovered three more which I do not believe have been reported:
1. in complex mode, press f - (i) to temporarily display the imaginary component. While the temporary display is up, press a single digit key, as if you were starting to key in a number. As soon as the temporary display of the imaginary component goes away, the digit you pressed will be displayed, and the display will be flashing. Pressing another digit key will continue entry of a multi-digit number beginning with the one that was already entered, and stop the flashing display. Pressing any function key will execute the function on the flashing number and stop the flashing display. If you press more than one digit key while the temporary display is up, the flashing will not occur. On my 15C Classic, key presses during the temporary display are simply ignored.
2. in any mode, press f - PREFIX to temporarily display the full mantissa. While the temporary display is up, press a single digit key, and you will get the same behavior as above.
3. in any mode, press g - MEM to temporarily display the memory allocation. While the temporary display is up, press a single digit key, and you will get the same behavior as above.
I tried to think of other temporary display modes which might exhibit the above behavior and could not think of any. You can of course execute PSE from the keyboard which is a temporary mode of sorts. On the 15C Classic, keyboard input during the pause is ignored. On the 15c LE, input will be accepted as in the above examples and displayed after the Pause ends, but the display does not flash.
I point out the above to hopefully aid in producing a new bug-free rom by documenting all inconsistencies found with the current one.
edit - found another instance, changes in italics above.
Edited: 18 Nov 2011, 12:23 p.m. after one or more responses were posted