Client details sometimes not being sent

[Tychodewaard]

In the test setup all is well. Clients can buy stuff and client details are as expected within NBS and in the e-mail.
In the live setup there was an order without the details.

In Analytics I can see that the person was using Windows, Chrome 61.0.3163.100 (stable, current version), 1260x920, the time on the payment page was 11:42 (so, pretty long).