Grid becomes unmodifiable after a piston penetrates nearby Safe Zone
To reproduce this bug, you can just create a grid near the Safe Zone of a NPC Station, with a piston and a source of power. You can notice that before extending the piston, you can grind some block as you wish. Then, extend the piston so that it enters the Safe Zone. Once it is in, you won't be able to grind anything from the grid, should it be the piston itself (which I would understand) or any other blocks. Moreover, if you retract the piston, the grid won't be in contact at all with the Safe Zone, but will still be invincible.
You can't add any block to the grid either, trying to place a block doesn't do anything. You can create a grid that is aligned to the invincible one and then connect it so that they form one grid. The resulting grid will also be unmodifiable.
I have the same bug 
Hello, Engineer!
Thank you for your feedback! Your topic has been added between considered issues.
Please keep voting for the issue as it will help us to identify the most serious bugs.
We really appreciate your patience.
Kind Regards
Keen Software House: QA Department
Hello, Engineer!
Thank you for your feedback! Your topic has been added between considered issues.
Please keep voting for the issue as it will help us to identify the most serious bugs.
We really appreciate your patience.
Kind Regards
Keen Software House: QA Department
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