For a bit of technical explanaton on the terms:

In computer science, *true random number generator* is considered such which offers pseudorandom numbers from a large enough set of seemingly random data, so that the numbers generated can not be replicated in practice because the data, from which they were created, is too large and "random". For example, using large amounts of user input as the basis of random numbers is typically considered *true random number generating*.

In contrast, *pseudo-random number generator* is one which works on much smaller set of user data to produce seemingly random numbers. For example, an algorithm which is fed the current time in milliseconds and always produces the same number with the same time, is considered *pseudo-random number generator*. Probably the most commonly used random number generator, glibc's rand(), is an example of such algorithm.

Of course, neither of these are actually truly random. Computers are incapable of producing true randomness (except by the 0.000000000000000000000000000000000000000000001% chance of enough electrons quantum tunneling to just the right spot -- though even that might not be truly random) and by most part, so are humans.

It would technically be possible that the random number generator used by NWN is either a) too simple or b) deterministic (meaning, it returns same number with same seed) and being given same seed multiple times. I find it likely that it is glibc's rand(). While too simple for certain applications, it should be well good enough.

Now for the statistical stuff:

If you roll d20 400 times, it's likely that you roll any three numbers in row once while if you roll d20 8000 times in a row, it's likely you roll a streak of three 1s once.

Now the problem there is that human brain has the habit of making patterns out of anything. So when you require 10 bash attempts per chest and bust open 40 chests during a month, you're very likely to roll the same number three times in row. There's a 25% chance that those numbers are from 1 to 5 and 25% chance that they are from 15 to 20. Whichever it ends up as, we pick it up as either unusually lucky or unusually unlucky.

We also pick rolling, say, 1, 5, 3, 3, 4 as unusually unlucky. But rolling a number between 1 and 5 five times in row, is likely to happen when rolling 1000 times. Now, we tend to find those patterns from all rolls we make - not only chest bashing and crafting, but also saves, attack rolls, etc. And there are many of those in a week. It's a slippery slope, too: We may roll 1-5 three times in a row, then roll 11 and 8, then roll 1-5 another three times in row. If the 11 and 8 weren't enough to bash open the chest, in our brain the pattern of unlucky low rolls continues.

Regardless -- I suppose there is the off chance that the random number generator is either prone of generating the same number in specific seed ranges or its seed is supposed to be refreshed but isn't. Even so, in my own experience, there's no gross problem with it and any problems with it do not result in drastic alterations of game balance.