Restarting custom private networks - `cardano.node.Forge:Error:35`

I’ve set up a custom private network running on docker, for now it’s composed only by an SPO node and a relay node. I interact with using cardano-cli connected to the relay node socket.
When I first start the network it seems to work perfectly.

But if I stop and I restart it after a while (I mean stopping both the nodes) the SPO node gives out this error:

[360dd341:cardano.node.Forge:Error:35] [2023-04-17 13:08:32.00 UTC] fromList [("credentials",String "Cardano"),("val",Object (fromList [("kind",String "TraceNoLedgerView"),("slot",Number 246645.0)]))]

The slot number I get here seems to be too high (246645) compared to latest one where a block has been mined:

cardano-cli query tip --testnet-magic 42
{
    "block": 2435,
    "epoch": 0,
    "era": "Babbage",
    "hash": "d3d25ef8eed71ba91f8b845773dbea0c3d4cb14406a182b208bc08b1032addfb",
    "slot": 57035,
    "syncProgress": "100.00"
}

This is the complete output I get: https://termbin.com/7ugoy

Instead if I update startTime and restartTime in genesis files I get the same Forge:Error error but with different paramethers:

unbox-cardano-network-node-spo-1    | [636f9a39:cardano.node.Forge:Error:35] [2023-04-17 13:33:16.00 UTC] fromList [("credentials",String "Cardano"),("val",Object (fromList [("kind",String "TraceSlotIsImmutable"),("slot",Number 20.0),("tip",String "d3d25ef8eed71ba91f8b845773dbea0c3d4cb14406a182b208bc08b1032addfb@57035"),("tipBlockNo",Number 2435.0)]))]

In particular the number slot number (20 here) keeps increasing every second (my slot time is 1 second) until it reaches the tip slot I got with cardano-cli (57035 according to the output above) and then the network starts working again. But this means that if the network has been down for n hours I’ve to wait n hours when I restart it before it becomes usable again.

Why does this happen? What can I do to avoid this?

I’m struggling with this issues since weeks without luck :frowning: Any hint/help/suggestion (even if you are not sure) would be extremely helpful for me!

Thanks

PS: I’m using official 1.35.7 docker cardano-node images