Do the tablet pieces stop appearing after you have finished with that puzzle? I am short 2 rare ones and have not seen ANY for 2 days.
I also just want to add that I miss the shell, etc. on the roof of the hut that shows you have found all of a certain type of collectable.

No, they should still appear but very infrequently it seems. Not as often as the other three types of collectibles. I found a couple rare after I finished the puzzle you are talking about.

Actually, collecting all of one collection improves the physical aspects of the science building. When I got all the turtle shells, the lower walls were finished off, the gate to the alchemy pot got finials on each piece, and the top walls became better fitted, so the collections DO give you things in the labs. They are just more subtle. I wonder if you MISS a piece of the tablet, if it will show up again....

The Chief might help??

I have been clearing rubble and am at 70% with only 5 pieces found. I have been watching whenever they are clearing and pause it when I am not able to watch. Chief is directing. I just hope that the other 7 pieces magically appear before its complete!

Is there a sequence to when they show up, or is it just luck?

I just got 3 rare tablet pieces in a row.

They also appear after it is complete, but very, very infrequently

I actually got a piece before I even started the puzzle!






[SPOILER! HIGHLIGHT BELOW]
The chief pointed out a "rare" collectable and wala!

Yes, if you miss a tablet piece, it will show up again. I've tried it on a test tribe. And once you've gotten a tablet piece, that piece won't show up again.

I hate to tell you but I'm a couple of days past beating the whole game and still only have 7 pieces of tablet. (have everything else other than 2 feathers), so unless my case is extreme, I doubt youre going to get them by the time you finish clearing the rubble.