Affected version: GregTech 6.14.09
I have a Battery Box (MV) filled with 4x Lead Acid Battery (MV). I attached a Button Panel Selector Cover to the top of the battery box, used a chisel to change the design so that I could see the numbers on the keys, and then pressed the “1” button so the Battery Box would only output at most 1 packet to allow the battery box to emit at most 128 EU/t. Then I accidentally put a block on top of the battery box (the same side with the Button Panel Selector Cover), broke the block, and the design of the cover reverted back to its default, without numbers.
This happens when you place a block in any adjacent space, not just on the same side as the cover.