The paddle " character "  was a little glitchy while playing the game. The first guess was the wiring from the counter to the shift register but it  was OK.

Second guess was some glitches found in the capture by logig analyzer

A 100nf capacitor was placed from the output pin (pin 1 - UP ) to ground and the glitches disappeared from the capture and the behavior of the paddle character now is smooth as expected!

PCB and schematics were updated