Token-based persistence is enables; it seems similar to what you describe. All about timing -- same token login at the same time will create two entries. It wouldn't be a problem if it wasn't for the fact that only one will contain the responses and it may not be the one displayed.

But with reloadAnyResponse : if someone use lua proxy (for example ) he can not open the survey due to a 409 … (try to load the same survey/response id).
On a windows IIS server, with some issues with speed at this time …

With «Token-based persistence enable» it must not have 2 response line. It's clearly an issue.

Denis

I agree -- it seems that the process of adding the response line is started twice. Probably because both webcalls are started before either can make the first entry. The different seeds seem to confirm that.
Let's see what happens with the bug tracker.

Thanks for thinking along with me, it helped and it's appreciated!

Yes : but even with a low speed server (Virtual machine) with an SQL server on another virtual machine : i can't reproduce such issue …

Your database must be particularly slow ...

I haven't noticed it performing timed tasks any slower than instances on other servers. It may be a caching issue; server side, I guess. It is a shared host, so it's not always easy to see what goes on in the back. I'll raise it with the host too, let's see what they can see.