The Addendum is useful for clarifying what may otherwise be odd or confusing events that can happen during the game.
Re-Roll Blanks - This means that you may pick up dice which you have rolled already that were Blanks and roll them again.
Re-Roll Success - This means that you pick up dice which you have rolled that are not Blanks, and roll them again.
Re-roll All - When instructed to Re-Roll All, this occurs after all dice have been rolled and subsequently re-rolled if required for a special rule. For any Re-Roll All scenario, after you have completely finished rolling, you will pick up all the dice and roll them as if you had never rolled them before, meaning you would apply any other re-rolls again. Effectively, this rule resets the entire dice roll pretending like it never happened.
No Stacked Re-rolls - Re-rolls do not purposefully stack. This means that if you have several rules in play which allow you to Re-Roll Blanks, Successes, or specific symbols, you would only ever do so one time. Furthermore, once a Rule has been triggered to force a Re-roll, no further Rules may be triggered which would force a subsequent Re-roll. In the case of a Re-roll All, you are effectively starting the entire roll over again. In this case, rules which apply the Re-roll of Successes, Blanks, or other symbols are in effect for the second roll, but are then again subject to the No Stacked Re-Rolls rule. The Re-roll All is subject to this rule as well meaning you are not forced to Re-roll All twice (except for Tempt Fate).
Multiple Sources of a Rule
Sometimes, Models may come under the effect of a single rule but do so from multiple sources. The most common example of this is the Hindered Universal Special Rule.
Example of Multiple Sources
Suppose a Model is in Difficult Terrain and it is also currently under the effect of Night Time. In this example, the Model is receiving the Hindered Universal Special Rule both from the Difficult Terrain and from the effects of Night Time.
Furthermore, certain Special Rules may come into play which either eliminate a Special Rule entirely or eliminate a Special Rule from a specific source.
For those Rules which eliminate a Rule entirely, this will apply to ALL sources. For those which target a specific source, it only eliminates the Rule from that source and a Model receiving a Rule from Multiple Sources would still be affected by the Rule.
Rules Do Not Stack Rule - A Model can only ever have a Special Rule one time, regardless of how many sources it is receiving the rule from.
Specific Sources Example
Marcus has a Model standing in Difficult Terrain and also is under the effect of Night Time. Both of these Rules cause the Model to have the Hindered Special Rule. However, Marcus's Model also has the Sure Footed Special Rule which means that it can ignore the effects of Difficult Terrain. Marcus's Model is still Hindered because the Sure Footed Rule does not eliminate the Night Time source, only the Difficult Terrain Source.
All Sources Example
Using the above example, we find that Marcus's Model is also with 6 inches of a Ramaltas Model. The Ramaltas has a Special Rule which reads that all Friendly Models within 6 inches are never Hindered. Since the Ramaltas's Special Rule targets all ways a Model can be Hindered, Marcus's Model is no longer Hindered.
Dice Facing Reference
As a reference, these are the facings found on each colored die: