This seems to be related with a new feature in the private builds for missing custom blocks, but it shouldn't be triggering in this case. Do you happen to have another behavior called "Health" in your game before importing the resource pack? I'll run some tests on my end to see if I can reproduce the issue.
Edit: I tried on b11028, importing the resource pack into a brand new game with only one scene, and I cannot reproduce the issue. I can only test on Windows, and I'm not sure if this issue is OS dependent. Can you do the same test on your end, importing the resource pack into a new game with only one scene?