question about the HP49g+ F3 and F4 keys

[grossi]

Good day to all!

Some years ago I bought an HP 49G+ (my serial begins with CNA515), without testing it a lot, and then I left it it in the drawer. Since now my old HP 48GX begins to have some problems, today I have decided to begin to use it.

However, I have noticed that in my calculator, contrary to all the other keys, the F3 and F4 keys (the central ones under the display) don't click at all and don't give me any touch feedback. They just slightly move, but they don't go down and then up again sharply: I have the confirm of the success of my operation only from the result on the display.

I know about the problems with the old HP 49G and HP 49G+ models, but I am wondering if this particular behavior is a standard "feature" or if it is a problem of my specific unit.
Do you have experienced the same fact on your HP 49G+ calculators?

Can some HP 49G+ owner give me an answer?
Thank you in advance!