I have had a similar issue, the liquid was all but clear and consisted of a water/ fuel mix.
The concentration of fuel in this liquid was enough to chemically melt the black Oil/water separator.
I have recently replaced the oil/water separator and fitted a new injector.
Its too early to say whether it has cured this problem and also an issue I have been having of fuel contamination causing the oil level to rise.
These problems seemed to be at their worst during the colder months of the year, so it might not be until winter that I will truly know
Update
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** oil level rising might not be an issue after all, check out CSC blog on checking your oil level **