When I call the fee_history method from the web3 library, the polygon node returns a non-null EIP-1559 base fee.
Request on eth_feeHistory returns response:
{'jsonrpc': '2.0', 'id': 0, 'result': {'baseFeePerGas': ['0x22', '0x23', '0x27', '0x2b', '0x30'], 'gasUsedRatio': [0.5150423384224325, 0.9958615949232461, 0.9957990374455649, 0.9990101827216755], 'oldestBlock': '0x17e3f8c', 'reward': [['0x8c063bbc9', '0x1202ddc65e', '0x174876e7de'], ['0x80ccb79cd', '0xba43b7400', '0x15896dfcef'], ['0x72ffed179', '0x730fe0971', '0x9502f8fd9'], ['0x7fc7076e6', '0x7fc7076e6', '0x8ddbeaff0']]}} We see that the base fee is equal to [34, 35, 39, 43, 48]. It's on infura. But local node returns 22 Wei as the base fee for the next block.
However, on https://polygonscan.com/gastracker and https://polygonscan.com/blocks I see blocks with a base fee close to 0 Gwei (ex. 13 Wei: https://polygonscan.com/block/25035822) and blocks with a base fee of tens of Gwei (ex. 68 Gwei: https://polygonscan.com/block/25013644).
What is the real base fee on polygon chain, close zero Gwei or not? Is the formula for calculating the max fee in the form of (base fee + max priority fee) relevant? And why does a local node always return 22 Wei as the base fee?