Fork-off does not reset paraScheduler.sessionStartBlock

[sea212]

Chainspecs resulting from the fork-off subcommand use the original paraScheduler.sessionStartBlock value from the forked chain. This results in validators being unable to produce blocks, as the condition at >= session_start_block is not met.

[aurexav]

It seems that you are trying to fork a relaychain? This is designed for parachain before. Will check this later.