delegate call execution doesn't return data

[marcelomorgado]

The returnData is always empty when excuting a delegate call (Refs: https://github.com/zerodevapp/kernel/blob/dev/src/utils/ExecLib.sol#L54). Is there a reason for that?

[leekt]

good catch, adding fix for this on v3.1

[leekt]

it will be merged on #111