What is the best word to use in place of "unique, but due to your setup", without attributing blame?

Question

At work, we believe one of our customers experiences problems with our product due to their infrastructure. Their network is very busy and requests often time out.

We suspect that this is the cause of the problem and we've attempted to remedy it blind. We can't reproduce the issue using our own network, but have put features in place to fix the issue, if indeed that is the issue.

What we're struggling to find is a word that's suitable to describe this to the customer.

"We've been unable to reproduce the problem, but have put some fixes in place to help rectify what we think it may be. Your situation appears to be unique, due to your setup"

My manager has a single word on the tip of his tongue that best fits the part in bold. Do you have any suggestions? We're looking for a word that doesn't blame the customer, yet indicates that it's unique to them and unique to their setup. Some words that don't quite fit the criteria:

• special
• unique
• isolated
• anomalous
• abnormal

Answer 1

Although it may carry just a little of the connotations that your list of rejected ideas seems to avoid, consider idiosyncratic as a word that might gently convey the idea that the problem lies in local quirks.

M-W defines idiosyncrasy as

a peculiarity of constitution or temperament : an individualizing characteristic or quality

While the word's principal sense seems to be personal rather than institutional, it may well serve the intended purpose.