New customers are created without groups

[juanjico]

Hello!

 

I'm using PS 1.7.8.7 and just noticed that when a customer creates an account on my shop, it's created without any group:

But this don't happen always, some users get the groups correctly:

So, I'm really lost with this.

Anybody know what could be happening ?

 

Thanks!

 

Best regards,
Juanjo.