Sometimes receiving 1 fewer buff tick than you should

[Karlito]

When seeking blessing at an advocate (or relic) with the defensive blessing tree, you get only 29 ticks of santuary blessing (instead of 30). If you get a tick based prayer result, that one has the correct number of ticks.

Similarly, when you get a potion effect from an Arcane book, you get 1 fewer tick than the message says.

It's as if these effects are being added before status ticks are decremented during action processing.

[NearNihil]

I think that last sentence is entirely correct, it's generally how things are applied and that is usually (but not always) taken into account when granting status effects. It's kind of a toss-up whether these should all be pulled one way or the other, but the easiest way is to move the ones that have one tick too few up one without changing the underlying mechanics. It's also not super high priority as most of the off-by-one errors already have more than twenty ticks.