Slow turn-off time on PNP when driving 7 segment led
You would be better to measure the current through the 330 ohm resistors than the voltage- the current translates into light emitted whereas the voltage doesn't mean much once the LED current drops to near zero.
As well as moving the resistors as others have suggested, I suggest trying to digitally reduce the brightness from full to maybe 80-90% which will increase the interdigit blanking time by a factor of 4 to 6.
You could also replace the BJTs with MOSFETs 2N7000/BSS84 for a large increase in switching speed.