Originally Posted by
bankops
Don't confuse the various systems. While border crossings of EU citizens are not in a centralised system, the SIS (Schengen Information System) is. When the Dutch queried the SIS it may have returned a false positive regarding another individual and have had instructions to inform a particular agency about movements. This is the most likely scenario for your case. Kind of like the no-fly TSA list except they don't provide a redress number to you to avoid the false positives. For non-EU citizens who do not need a visa, there are centralised databases (ETIAS and RRS), but they are not yet operational. Slated for 2022 though.
SIS is not an entry/exit tracker even for me.
I have enough access and experiences — even same-day experiences — to know what was going on with my own circumstances. It wasn’t SIS that kicked back a false positive. It was just the Dutch.

I use US passports at Schengen passport control, as I’m not a dual-citizen, and there were days last year where I crossed Schengen passport control even 3-4 times in a day.