When I take a horse through the nether portal the score is completely removed. Tags stay on the entity.

Steps to Reproduce:

1. Create a scoreboard objective
2. Set the the objective to the sidebar display
3. Summon a horse
4. Use the scoreboard command to give the horse a score
5. Give yourself a lead
6. Attach lead to horse that has a score assigned
7. Step into a Nether portal

Observed Results:
The score for the horse is no longer in the sidebar

Expected Results:
I expect the score to still be there.