HP12C: date functions and flashing display ?!

[Dieter]

First of all: I do not have a real 12C, instead I am using HP's own emulator which I think is supposed to behave like the real thing.
And here I noticed something that I cannot explain (yet):

In some cases the date functions (ΔDYS and DATE) return the result with a flashing display if the function is executed in a program (!).

Example:

1,011900 [ENTER] 1,012000 g[ΔDYS] => 36524

Fine. Now do the same thing within a program.
Clear program memory, then enter ΔDYS as step 01.

f[P/R] f[PRGM] g[ΔDYS] f[P/R]

1,011900 [ENTER] 1,012000 [SST] => 36524 flashing

Is this the same on a real 12C or a quirk in the emulator?
If this is by design: what causes the display to flash?

Dieter