Is it a common problem for diesel fuel to get into the engine oil while regenerating the car?

My 2016 Volvo V70 with 7000 miles, three months post first annual service, put up a message saying it was due an oil change and at next start up showed an amber engine block icon with 'check' below. I took it to the dealers from whom I had purchased the car. They said diesel fuel had got into the engine oil while regenerating the car and they would drain and change the filter for free. No paperwork has been generated. Is this a common problem in this car? The dealer's response was not clear to me.
Yes. Common. Especially if you do repeated short runs from cold starts. The system will attempt to actively regenerate, but if you shut the engine down while this is happening, the extra fuel injected into the engine to accomplish the regeneration will simply sink into the sump oil. Diesel cars should have a DPF regenerating warning light to tell you not to switch off until regeneration is complete, but I don't know of any that do. Telltale signs are the fans remain on when you leave the car accompanied by a smell of burning. If that happens, get back in and drive it for 10 miles or so. Very inconvenient, but that's what diesels have become if used for short runs.
Answered by Honest John on

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