colu server returns errors, or get stuck, on "getAssetData"

[fed-franz]

Hello,
It is not the first time it happens...
when i try to request asset data I get an error like this:

The body of the POST request:
{
"jsonrpc": "2.0",
"method": "coloredCoins.getAssetData",
"id": "1",
"params": {
"assetId": "La74ypGoSZotxx1qbBFc1y7Sk2TKPq8UcGFrSY"
}
}

The body of the response:
{ jsonrpc: '2.0',
id: '1',
error:
{ code: -32603,
message: 'Internal error',
data: 'Needs assetId' }
}

or get stuck until the connection is reset

Others commands work fine, until, after a getAssetData request, the server gets stuck,
in which case, all comands produce the same effect (for a while...).

My configuration before starting colu is:
$ export COLU_SDK_RPC_SERVER_HTTP_PORT=8081
$ export COLU_SDK_NETWORK='mainnet'
$ export COLU_SDK_API_KEY='...'
$ colu
(or '$ node which(colu))
Is it a bug or something I misconfigured?
Is there a way to fix this problem?