HELP - Multiple MCP23S17

- Arduino board: Arduino Leonardo

- Arduino IDE version 1.8.9

I built a custom board with two MCP23S17.
They are on the same Chip Select, with different addresses (000 and 111).
However, readGPIOAB returns the same for both chips, hence it appears I am not able to address them correctly.
Reading the documentation i was under the impression this was a legit configuration.
Do they require different CS? If so, what is the value of having the address pins?
By the way, reset pins are connected to VCC. I did not implement a reset circuitry, which was working fine with a single IC.
Help appreciated!

Start with the library entry point readGPIOAB and the MCP23S17 addressing behavior described for an Arduino Leonardo with two devices sharing chip select. Reproduce the identical readings using address pins 000 and 111, then compare the result with the documentation; done means establishing whether the configuration is supported and recording the confirmed behavior.

Written by the indexing model from the issue text.