I suddenly found there is an reorg happened today whose depth is 3 on Etherscan.io here. The uncle blocks is at height
9919331 and the hash is
0x3b1161a8bdf5107f1dc2092781798d143b5ae66b6604823630b57f5d9450e1cb. However I further checked the structure of the blockchain history and found the structure is like this:
0xa0f0 => 0xc535 => 0x7ea3
0x7ea3 represent the blocks (first 16 bits of their hashes) in canonical chain, while
0x3b11 is the uncle block reported by Etherscan with reorg-depth 3. The hash of
0x3b11 is included as uncles in the block
I am very confused why Etherscan reports this uncle blocks as reorg-depth 3. It seem this reorg only discard one block (i.e.
0x3b11). Is this a problem in Etherscan? or are there some uncle blocks overlooked by me?