It looks like eth_getBlockTransactionCountByNumber is not accounting for the State Sync transactions.

Version: bor/v0.2.16-stable-f083705e

This also happens on the Erigon erigon/0.0.3 release with the latest snapshot.

How to reproduce:

{"jsonrpc": "2.0", "id": 1, "method": "eth_getBlockTransactionCountByNumber", "params": ["0x20f9b80"]}'

Expected Output:
0x8f (143)

Actual Output:
0x8e (142)