In the middle of a forest when Claire and young Ian are digging a hole to bury Mr. Christie's body, and an old woman comes upon them, they just happen to have not one, not two, but THREE shovels to complete the task.
Immediately after Brinna gives birth, there is not one drop of blood on her nightgown or the cloth the baby is wrapped in.
When Brianna and Roger and Jemmy and Amanda arrive back in the future, they have no modern clothes, no money and no health insurance to cover the cost of surgery for Amanda, which makes no sense.
After all of their gut wrenching, lengthy, emotional, "final" goodbyes, all Roger and Brianna and their children needed to return from the future anytime they chose were more gemstones.