claim-prep.py produces KeyError: 'block_height'

[whysthatso]

python claim-prep.py --not-tails claim_save_file bunch_of_addresses

i've ran it once successfully, but upon rerun, it fails with this stacktrace

Traceback (most recent call last):
  File "claim-prep.py", line 43, in <module>
    vdb = ValueDb(settings)
  File "/home/user/coins/forkdrop_suite/lib/value_db.py", line 23, in __init__
    self['addrs'] = self._get_address_info(settings, addrs)
  File "/home/user/coins/forkdrop_suite/lib/value_db.py", line 44, in _get_address_info
    return [BlockchainAddressInfo(settings, addr) for addr in addrs]
  File "/home/user/coins/forkdrop_suite/lib/value_db.py", line 44, in <listcomp>
    return [BlockchainAddressInfo(settings, addr) for addr in addrs]
  File "/home/user/coins/forkdrop_suite/lib/address_info.py", line 143, in __init__
    tx_block_map = self._get_tx_block_map(ins, outs)
  File "/home/user/coins/forkdrop_suite/lib/address_info.py", line 182, in _get_tx_block_map
    self._iter_tx_blocks(ins + outs)}
  File "/home/user/coins/forkdrop_suite/lib/address_info.py", line 181, in <dictcomp>
    return {h: height for h, height in
  File "/home/user/coins/forkdrop_suite/lib/address_info.py", line 178, in _iter_tx_blocks
    yield h, d['block_height']
KeyError: 'block_height'

i did run sync-forkdrop-data.py in between, changing the content of forkdrop-data.json, if that matters. reverting this change to the latest git commit did however not fix this problem.