print_coinbase_height.py

#!/usr/bin/env python3
"""Search for blocks where the BIP34 indicated coinbase height is > block height.

Uses Bitcoin Core's test framework."""
import time

from authproxy import AuthServiceProxy
from script import CScript
a = AuthServiceProxy("http://<user>:<password>@<ip>:<port>")

START_BLOCK = 1
NUM_BLOCKS = 227940 #BIP34 activated at height 227931

with open('coin_base_heights.csv', 'w') as csvfile:
    csvfile.write(','.join(['block_height', 'coinbase_height']) + '\n')
    heights = []
    for block_height in range(START_BLOCK, START_BLOCK + NUM_BLOCKS):
        if not block_height % 100:
            print("Processing block at height {}".format(block_height))
            print("Time: {}".format(time.strftime("%X")))
        block = a.getblock(a.getblockhash(block_height))

        tx = block['tx'][0]
        script = CScript(bytearray.fromhex(a.getrawtransaction(tx, True)['vin'][0]['coinbase']))
        if script[0] == 1:
            BIP34_height = int.from_bytes(script[1:2], 'little')
        elif script[0] == 2:
            BIP34_height = int.from_bytes(script[1:3], 'little')
        elif script[0] == 3:
            BIP34_height = int.from_bytes(script[1:4], 'little')
        else:
            # first byte will be 3 until height 16,777,215
            BIP34_height = 0

        if BIP34_height > block_height:
            heights.append([block_height, BIP34_height])

    heights.sort(key=lambda x:x[1])
    csvfile.write("\n".join(["{},{}".format(h[0], h[1]) for h in heights]))

results.txt

block_height,coinbase_height,equal
164384,1983702,TRUE
169895,3708179,TRUE
170307,3709183,TRUE
171896,3712990,TRUE
172069,3713413,TRUE
172357,3714082,TRUE
172428,3714265,TRUE
174151,5208854,TRUE
176684,490897,TRUE
183669,3761471,TRUE
196988,4275806,TRUE
201577,5327833,TRUE
206039,7299941,TRUE
206354,7299941,TRUE
209920,209921,TRUE

You can reduce the number of RPC calls down to one by using getblock with verbosity level 2 (removes the getrawtransaction call) and getting the block hash for the next block with the nextblockhash field of getblock's output (removes the getblockhash call).