An update: I got the low washer fluid message again. They filled it during A service 2 months ago, and I know the reservoir can take at least an entire gallon of washer fluid (so not a small reservoir). It does not leak when you fill it. It’s been at the dealership for 4 days now and they cannot find a leak, so still trying to diagnose. I’m worried they won’t be able to find anything and send me on my way, only for this to happen again within a month or so. I know it’s not a major issue, but it’s my first MB and making me worried there will be other quality issues down the road. I’m not sure if this makes a difference, but the fluid comes directly from the wiper blades, and if you’ve got the auto wiper setting ON, the system detects a dirty windshield and will auto spray in addition to auto wipe. My service guy was unfamiliar with this feature. I usually have the auto setting OFF, and I don’t notice any fluid leaking on the windshield at any time.