@adavidm
Thanks again for your interest, sadly nothing solved problem. I brought the value BLTOUCH_DELAY to 1000 without results. Then I tried with HOMING_FEEDRATE_Z before with 5x60 an then 6x60. Probing speed is visibly increased but issue persist. I think I will buy an original BlTouch.

Thanks a lot for your tips, I will try them asap and I will tell you if they work.
Excuse me for the wrong place I posted the issue. I found the post with Google and I didn't noted it's Duet dedicated focusing my attention on Bltouch.

I tried to send m558 r1 and m501 and nothing changed.

Searching in Marlin with Arduino IDE, in configuration.h I found this line that confirm LCD information:
#define DEFAULT_MAX_FEEDRATE {400, 400, 4, 25}
but I found nothing about M558.
Reading about parameter of m558 instruction I found this:
Rnnn - Z probe recovery time after triggering, default zero (seconds)
It seems could work to stop bouncig but in any case I have no idea about the value of parameter I could use and actual T value.

Thanks Scachi and dc42 for your fast response.
Unfortunately I bought my A6 3 months ago without any previous experience on 3D, I'm a noob and I have some problem to understand your tips.
I installed with success Marlin 1.1.8 and BLTouch (clone) works but with alternate results and I suppose becouse of this bouncing.
On printer LCD I read: Vmax X & Y =400; Vmax Z=4; Vmax E=25 Are these the values I have to change? Or have I to use Pronterface to send some commands? And what could be correct values?

@dc42 I suppose you are speacking about original Anet firmware, I searched for it but unfortunately it seems scarce.

@Scachi Hi, I know it's a hold thread but I have the same problem. Can you tell me how you solved it?