mine craft 1.12.2
mine colonies 8.5941

Lets say. builder.

Builder is requesting an item Say a Bed. You have 4 beds in your inventory. You right click on builder and then click on request. You then see he wants 1 bed. you click on "FULFILL". IT removed EVERY BED from your inventory and give it to him. It doesn't just give what he asks for which is 1.

A quick look at the code WindowCitizen.fulfill()
It looks like it is using the wrong variables for the count when sending it over to the server.

MineColonies.getNetwork().sendToServer(new TransferItemsToCitizenRequestMessage(citizen, itemStack, isCreative ? amount : count, citizen.getColonyId()));

var amount = request amount
var count = amount in players inventory.

so based on the if statement isCreative means in creative mode send over requested amount in survival send over the players entire inventory.

I would think this should be reversed.

Yep you are right
Pushing a fix to our fixes branch now :D

check out #1814, 1817. I put the fix for that issue also. Both are the same issue.

Seen thank you. I am working on those directly after dinner

Should be fixed in the newest version, should be on curse in a few minutes