When most blueprints have been unlocked, tablets can be "empty" even though there are still blueprints to unlock. It seems that tablets randomly generate options, but when there are only a few options remaining the random generation returns no options more often than not. I had 10 tablets and a few unlocks remaining, but even spamming them open/closed dozens of times gave no blueprint options.

Gameplay

Angry

0.0138966

Yes

1.0.7