Xtol can have problems, known as "The Dreaded Xtol Failure", no matter what water you use. I have had it fail with tap water and distilled water both. Stock & diluted. One one litre packet and three 5 litre packets. All mixed and the stock solution volume measured before adding the water to dilute, on those I used diluted.(posted 8622 days ago)The packaging problems most widely known were with the one litre packets. Yet if you will check with your dealers you will most likely find many incidences of the 5 litre packets leaking powder from part A. Nice white powder all over the shipping boxes, dealer counters and your darkroom. It is a problem as recently as 3 weeks ago.
While Xtol is very nice when it works, it is a lot like trying to have a whore for a girlfriend. It just isn't trustworthy.