Birch Fence missing

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

After I mine for some time, some of the birch fence was missing, it should not be missing.

What actually happened was...:
After I mine for some time, some of the birch fence was missing, it should not be missing.

Steps to Reproduce:
1. I put a birch fence
2. I mine underground for a few minutes or 1 hour
3. some of birch fence are missing, in screenshot the fence should be connected but missing