How does forfeiting movement and having the propelled rule interact?
Example: A Pyg Battle Brig is damaged by a Stranglehold.
It chooses to forfeit movement and shoots.
Can it now advance 12‘‘ at the end of the activation?
Since it advanced less than 12 at the beginning and the rules state that forfeiting movement does not impact other movement abilities?
Or is there some rule that prevents this?
Following as I would also like to know the answer here 
Here are the options available to models during the Normal Movement portion of their activations:
Propelled says (quoting from memory; apologies if it’s slightly misquoted):
So, per Propelled, that Battle Brig cannot choose:
It does not have the ability to slam or make trample power attacks.
The only two options remaining to the Battle Brig are:
If you want the Battle Brig to move at all, you need to choose Full Advance, because that’s the only remaining option that allows for an advance.
If you’re affected by some effect that requires the model to forfeit its normal movement, then you must choose that option instead. 
If you forfeit movement, you have zero movement available during your normal movement, and thus your “remaining movement” is still zero at the end of your activation.
So: unless we get Infernal/developer statements to the contrary, a Propelled model that forfeits its Normal Movement does not get to advance due to Propelled.
Valid reasoning. Thank you.
However it highlights the core of the issue.
If you forfeit movement, you have zero movement available during your normal movement
Is there a reference in the rules for this?
Because I have also heard the reasoning
If you forfeit your movement you choose to advance 0 inches and not change facing
It would probably come down to exact wording here, so an Infernal ruling would help a lot.
Well lets ask one then. @elswickchuck how is this intended to work? Cimbat action and repo 12? Or no movement at all if you shoot?
That “forfeit your movement is really ‘advance 0 inches and change facing’” rationale is from an older edition. That is not valid any longer, because the core rules have changed.
Case in point: facing does not exist in MK IV.
Those options in the rules screenshot are mutually exclusive. The rule literally says “choose one”. You can’t Aim and Full Advance. You can’t forfeit movement and charge. You can’t charge and trample. And so on, and so forth.
Because there’s no special definition provided in the standard rules, we have to go by the standard definition of words. “Forfeit” really means “forfeit.”
If you want your model to advance, and your only options are “Full advance” and “Forfeit”, there’s no hidden, secret rationale; you have to pick “Full advance,” I promise. 
i think it can still advance. the brig (and all things with propelled) don’t even have a normal movement stat, so things that decrease it’s movement don’t actually effect it at all. in other words, things like speed buffs or decreases.
The brig forfeits it’s normal movement and then propelled checks to see how far the brig moved (0"). therefore, it can move the remainder at the end of it’s activation
As I read it, key word might be “remaining” movement in propelled rule.
Forfeating movement should not let any remaining movement, as you forfait movement as a whole, right?
Its not that you choose to advance 0 by forfeating unless i missed something in the rules. Its just that you skip the movement itself, therefore there is no “remaining” movement as there is no movement at all.
Does that make sense to you?
yes but the word remainder here means, “however much less than 12 it didn’t move”. it doesn’'t say the remainder is “how much normal movment it has left” or something like that
also, i’m pretty sure Deneghra’s feat, or any other possible spd buff or decrease doesn’t affect propelled at all.
a remainder in maths is defined as "the result of a subtraction equation " and in this case, the equation is
“12- x” , where x is the distance this model advanced during it’s normal movement
Effects that modify SPD have no effect on Propelled. The Propelled model’s SPD is “*”. You can’t add/subtract/etc. from a non-numerical value. 
And here’s the world’s simplest example for “forfeit.”
You have only $5 and nothing more. You forfeit your $5.
You now have $0. You do not still have $5.
And now, I give up until Chuck replies. 
yeah i guess i could go either way, too, waiting for an official reply
if i’m reading it right, i think the word “remainder” here could be replaced with the word “difference”.
both are used in math to mean the the same thing, result of a subtraction equation
I’ll take a look at some documents we have from when we play tested this rule as I do remember this same question.
Reading as written, if it forfeits its Normal Movement, it can not move during the Normal Movement at all, but would be able to move the whole rest of it at the end of the activation.
It is written currently in a way that says the model forfeits it’s Normal Movement, not it’s ability to advance at all during it’s activation or thereafter.
For example, Reposition allows models to move at the end of the activation even if they forfeited their normal movement, and the wording here is similar (“can advance at the end of the activation”).
Indeed the key is in the definition of what actually “remains”.
If you forfeit your movement in this example then you will not have any “inches” left to move at the end
Problem solved. Thank you!
sounds like a good answer. i’d figure the blimp would have an Achilles’ heel somewhere.