From the site, you can't create two trial extensionSolved

We tried to create two trial extension with the same customer id. The first got created, the second just showed me the first one, instead of creating another.

Is it again wanted?

EDIT: we just noticed that this behaviour happens if the second one is an offline trial extension. We can create more than one online trial extension.

You're right, this is a bug. We've fixed it.

Also, TA 3.1.2 is out that fixes another trial extension bug.