Cut it off, if it isn't necessary...

wilderness <100%hp 50%m 100%mv 2525tnl (52.54%) 3 AM> You failed to pick the door.
You learn from your mistakes, and your pick lock ability improves 1% (79%).
wilderness <100%hp 50%m 100%mv 2525tnl => + 0 exp

wilderness <100%hp 53%m 100%mv 2525tnl (52.54%) 4 AM> You failed to pick the door.
You learn from your mistakes, and your pick lock ability improves 2% (81%).
wilderness <100%hp 53%m 100%mv 2525tnl => + 0 exp

wilderness <100%hp 65%m 100%mv 2525tnl (52.54%) 7 AM> You failed to pick the door.
You learn from your mistakes, and your pick lock ability improves 3% (84%).
wilderness <100%hp 68%m 100%mv 2525tnl => + 0 exp

wilderness <100%hp 72%m 100%mv 2525tnl (52.54%) 9 AM> You failed to pick the door.
You learn from your mistakes, and your pick lock ability improves 3% (89%).
wilderness <100%hp 72%m 100%mv 2505tnl => + some exp

wilderness <100%hp 76%m 100%mv 2505tnl (52.91%) 10 AM> You failed to pick the door.
You learn from your mistakes, and your pick lock ability improves 1% (90%).
wilderness <100%hp 76%m 100%mv 2485tnl => + some exp

wilderness <100%hp 69%m 100%mv 2485tnl (53.95%) 4 PM> You failed to pick the door.
You learn from your mistakes, and your pick lock ability improves 3% (93%).
wilderness <100%hp 69%m 100%mv 2450tnl => + some exp

...

wilderness <100%hp 88%m 100%mv 2350tnl (55.83%) 9 PM> You failed to pick the door.
You learn from your mistakes, and your pick lock ability improves 1% (99%).
wilderness <100%hp 88%m 100%mv 2300tnl => + some exp

Question: isn't it a some changes about practicing? or it's a buggy?

Sometimes!