I'm not positive about the reason for these 'errors', it may be due to a filled die, or simply a die that was wearing out:
2008 Coin 1

2008 Coin 2

2008 Coin 3

2008 Coin 4

2008 Coin 5

The following ones only have very minor 'bits' missing compared to all the 2008 ones.
LF = Left Finger: RF = Right finger
1994 and 1996
1994 Top of LF missing, most of RF missing
1996 Top of LF missing, RF broken in middle

1999 and 2001
1999 Top of LF missing, RF top 2/3rds missing:
2001 Tips of all fingers get shorter going to the right.

2002 and 2005
2002 RF almost gone, others indistinct.
2005 All very indistinct

2007 and 2009
2007 All fingers short
2009 Fingers short and indistinct

I'm sure that this has probably happened on practically all years to a greater or lesser extent, but I'm not going to go though all my coins again to see which other years might be affected. Too much work!