There are more than a few threads on other forums on the subject of biodiesel use in the MB 3.0L V6 turbocharged diesel engine. Most of the controversy relates to warranty issues. Basically, you can void the warranty if you use B5 or more blended fuel which results in engine damage. Since your chassis is probably outside the warranty, you'll have to respect the recommendations, but if anything goes wrong, you'd have to deal with it.
So, that said, MB recommends using B5 or less, but suggests that if you have no other choice, and use higher blends than B5, you should monitor your engine oil levels for TOO MUCH OIL in the crankcase. Unburned biodiesel can get past the piston rings and accumulate in the crankcase, causing a too much oil situation, and that can cause damage.
I've had to use B5 or better in my Navion, and have not seen any of the "too much oil" situation symptoms. I do check my oil at every fuel stop, as the manual recommends. I get my oil changed at a MB Sprinter dealer, and they've not said anything about it, nor have they noticed any dire problems.
If you have a PDF version of your 2015 MB 3500 Sprinter cab chassis Operator's Manual, do a keyword search for "bio-diesel" or "B20", and it will take you to the section on the use of, and warnings about, using bio-diesel fuels in it.
Bottom line, the amount you used is not a problem, and you can use up to B20, if you have to, as long as you keep an eye on the engine oil level in the crankcase. You don't have to change your fuel filter after B5-B20 use, unless you want to.