Can't create/edit recurring template

Hello,

I have an issue when I want to create or update a recurring template, nothing happens when I try to save my changes.

I checked my browser's network tab in order to find the actual error, and found this
"The value of the number field is already used." (not exact wording since it's translated from French)

After checking the source code, the "number" field is a hidden input containing the transaction number which is automatically generated. For me, it is RCT-00008

But it looks like this automatically generated transaction number already exists on my account, so I can't create or update any transaction because of this.

Hope this bug can be fixed or feel free to tell me if there's a workaround.

Thanks