There seem to be three blocks with valid BIP-54 coinbase locktimes at this point:
$ paste -d ' ' <(curl -s https://mainnet.observer/csv/date.csv) \
<(curl -s https://mainnet.observer/csv/coinbase_locktime_set_bip54_sum.csv) | tail
2026-02-15 0
2026-02-16 0
2026-02-17 0
2026-02-18 0
2026-02-19 1
2026-02-20 0
2026-02-21 1
2026-02-22 1
2026-02-23 0
2026-02-24 0
SELECT height FROM block_stats WHERE coinbase_locktime_set_bip54 > 0 ORDER BY height;
937404
937650
937744
So 937404 is actually the first one!