The tast screen quest gives 10 screens but players can only place them as 1x1. This is documented in Direwolf20's play as well as multiple times in the server.

I believe this only started happening around 1.2.10.

Same

1.2.13 official server, tried to place 3x3 block, only 1x1 was placed. I watched Ector's YT so I know that the whole 3x3 should be placed. Also after selecting the 10b water quest, the 1x1 block looked like a tank but I could not empty the water bucket into it. Delivering the bucket inside the questbook worked, and then the tank visuals showed that 1b had been filled in.

The NBT was changed for the screens, the quest in chp 1 should now award the fixed task screens with the appropriate NBT. Re-open/create a new issue if there are still issues after updating to 1.2.14