Well, except as she passes through the hole, that is. A similar error occurs as Mrs. Brisby reads from Nicodemus' book. In the Owl's lair, the spider descends behind Mrs Brisby on a strand of silk. As soon as it touches the ground, the silk line simply vanishes. As the ship departs Germany, watch the mice waving good-bye.
Diamonds Are Forever, But Stones Come And Go.
As Mrs Brisby learns of Nicodemus' death, her amulet is conspicuously visible. But, as she jumps onto the rock to warn the rats of Nimh's arrival, the amulet is gone. It doesn't reappear until after she's attacked by Jenner. During the swordfight sequence, Jenner sometimes has a tail, sometimes he doesn't. The design of Justin's feet changes back and forth over the film.