I don't understand buffs that have 'Charges do not stack'

[Lorevi]

The more common buffs like bleed/poison/etc make complete sense. But there's a couple of buffs in the game which display 'Charges do not stack' in the tooltip and seem to be exhibiting weird behaviour.

For example; 'Fast'. This is an example of someone with 1 stack of Fast gaining +2 speed (https://i.imgur.com/Ef29Hx1.png). This is an example of someone with 4 stacks of Fast gaining +8 speed (https://i.imgur.com/0UkELDg.png). What about this isn't stacking?.

Then applying these buffs seems to sometimes just not work. For example I use the item 'Steadfast Shield' (https://i.imgur.com/EYdQiEs.png) which can activate twice per turn each time giving me +1 Speed. The first time it activates it works fine and I get 1 stack of speed. The second time it activates I only get the heal and not the Speed stack.

This weird gaining thing works for other non stacking buffs too. For example Lets say I have the Armor 'Red Cape' giving me 3 stacks of provoke (https://i.imgur.com/F51xYY0.png). That works fine and I get all 3 stacks. My turn comes around dropping my stacks to 2; then I use the card 'Heat Laser' (https://i.imgur.com/2T8TR82.png) which should give me another stack of provoke, instead it just gives me the shield not the provoke stack.

I can't tell if this is bugged or how it's intended to behave? Me read on the phrase 'Charges do not stack' is that the effect doesn't stack but more charges means it would last longer. Instead it seems to be preventing you from gaining stacks in many instances which makes a lot of cards/effects significantly worse and prevent synergy between certain cards/items (for example the Steadfast Shield mentioned above. What is the point of the second charge if you can't gain the Fast stack?). If this is intentional it needs to be more clear how it behaves because the current behaviour is super jank and just leaves you confused as to where your buffs went.

[HAWAIIANpikachu]

Charges do not stack means that if you have different sources, the higher one stays. With fast for example, if you have 1 stack of fast and then gain 3 from a card. You gain the 3 stack of speed instead of going to 4.

[SgtNoGlory]

In terms of stacking, if you have multiple cards that apply it on the same turn, the highest value for the status takes over.

eg. Playing a +2 speed, then a +4 speed, and then a +2 speed again, the +4 speed is all that will remain. The only reason to play other speed cards would be to get the other affects of the card.

HOWEVER, in terms of speed, the enemies may have also applied slow at some point, in which case, new stacks of speed will first remove the slow, and then once slow is gone, speed is actually applied.

eg. if you have 6 slow on you and then you play a +2 speed, then a +4 speed, and then a +2 speed. The first +2 and +4 would remove the 6 slow, and then the +2 speed is what you would be left over with.

[TnJ]

If you use something that gives you +3 X and next turn it drops to a +2 aura, using a +1 shouldn't give you anything because your +3 and the +1 don't stack.

Heat Laser can't take you above whatever it says on the tooltip.

[DJDiceZ]

While the wording is awkward, what it actually means is: Charges cannot combine.