Indeed it is an object the avatar previously sat on.
The relaypart of the avatar remembers the UUID and checked it out; thet uuid is correct.
Also before the @sit command is send I send some rlv-command to unset restrictions. (sittp, tploc, tplm, unsit, sit).
The resitter should start after logging in and sat the avatar on the object sat before logging out.
Especially annoying is, that sometimes it works - sometimes not. And I cannot find a pattern. I am under the impression, that it works, if I look at the target object. But that makes no sense.