I have just had some XP2 processed by a lab in Bangkok.
All my previous rolls, processed by them and other labs, have produced negatives with a purple hue; and the resulting scans have been excellent.
This time the negatives were grey, and the images were grainy and muddy.
When challenged, they insisted they had used C41 (although charged me for B&W) and offered the explanation: "Purple negative was caused by fixer. It happened either C41 or hand-wash in the darkroom" (English is not their first language).
Will C41 always produce a purple tinged negative?