last fall (2023), I had to buy a sliver of land from my neighbor so I could put up a pole building garage.

I just checked OnX and that change is still not reflected in their data.

I checked it standing directly over my property corners. I wouldn’t trust On X if that was the only info I had on where I stood on public/private. 99% of the time I don’t need that accuracy, I am buried deep in National Forest land.

I had some surveyors come out to the farm last fall looking for 2 section corners. We had used OnX to try to get us in the general area. They said in their experience, OnX will put you within 50 yards of what it shows on a map almost all of the time. We ended up being about 40 yards off from the corner post.

We have a lot of property boundaries that are easy to identify on aerial imagery due to timber changes. Most of the time the property lines shown are within 30 feet of where they should be.

The ownership data is all dependent on how fast the county can make changes and how often OnX updates their property owner data. 6 months to a year out of date on recent ownership changes would not be unexpected.

Before doubting the app, which it does have some inaccuracies, know how accurate your phone is and the signal/amount of satellites your reading. Blocked signals, or worse, is reflective signals can throw you off a lot. All devises have a GPS U.R.E. (User Range Error) and can vary dramatically. Also most civilian devises track on a single frequency which enhances the probable error. If you have a devise that tracks in multiple frequency, and has a very low URE, you can get amazingly close. But then sending a MX Missile only has a 50% chance of hitting a 400 foot target.

Well, in all fairness, a MX doesn’t have to answer to trespassing charges.
A hunter, relying on OnX to determine if they are in the right or wrong to shoot is a dicey situation. Coverage density amongst multiple cell towers is required. GPS and clocking are vital to their accuracy.
From my experience with the Telecom industry, I wouldn’t hang my butt on the line with what you perceive to be accurate.

County tax maps are also not a substitute for a survey map.

Game wardens don't enforce trespass laws here. It's the local sheriff or P.D.

Game wardens don't write hunting/fishing without permission tickets in WI?

I've never heard of such a ticket here. I'd imagine if there was one, they'd work together, but a warden can't write a trespass ticket. Its not a hunting/fishing violation.

They have that ticket here in Nebraska but wardens here also have full power of any LEO, DUI, trespassing etc.

You have gamies, we have brown shirts. Brown Shirts are Alaska State Troopers.
Additionally we have Department of Agriculture, AKA USFS, and NPS Enforcement. You aren’t getting out of a ticket with talking with any of them in the field.

That seems odd to me. Not doubting you, just seems odd.