Brother, this problem is ETERNAL in AutoCAD and i already lost my hopes it will someday be fixed.
Layerstate is a troy horse, it seems will help u but it will stop you in so many ways.
Is pretty easy to fix but i think that autodesk does not give a care to AutoCAD anymore, that is the truth.
Can come here 500 ppl with beautiful profiles giving a full explanation seeking to receive from you the seal of right answer so in their profiles will show that they answered and solved the problem but the fact is that this is an error in AutoCAD. The viewport never keeps the layer state, if u back to model work, switch the layer states and back to layout to see how is each sheet you will see that its all mixed up and u need manually re-choose the layer state for each viewport, THERE IS NO EXCUSE THAT CAN EXCUSE THIS, ITS A ERROR IN AUTOCAD!!!!!!!!
Ppl here try to cover to protect autoCAD but the fact is that is an error.
And more, if you change the color of something in Model it will neverrrrrrr change the color in the viewports, and you will lose weeks trying to fix but everytime when you choose the layerstate the previous color of some layer will return to the previous color that you dont want.
Ppl can come here and give a beautiful answer saying "ahh all u need is click here and there and update..." but it seems to me they dont know that we work in Model and not in layout, we deal with project with a million lines on the screen, can just cant manually layer by layer and viewport by viewport and layout by layout update everything.
If ppl lose more time going there in support and demanding AutoCAD to change this in next updates instead of defending the indefensible once they know that its a error but they dont want to say it, this problem would be solved since 2018 or earlier.
Hugs from 2024 and the problem carries on...
@alexandresynth - this post has been edited due to Community Rules & Etiquette violation.