I called esri and got a tech guy on the line and he fixed the problem. I am attaching below the recap of what was done to get the layers to function.
To recap our phone call, you were seeing an issue in Collector for iOS 19.0.1 where one specific layer would not load in any web map. When you click the layer, you were receiving the error: "Code 2. Invalid argument". To fix this issue, we inspected the fields list in ArcGIS Online. We noticed that some fields had domains. We added a space to one value in the "Code" field in each domain, removed it, and saved the domain. On the backend, this changes the name of the reference to the domain. Like I mentioned, there was a known issue with the naming convention of these references that became apparent with the last release of ArcGIS Online. Simply resaving each domain fixes the issue.
Sue Borchardt
PhD Candidate - Teaching Assistant
Department of Geography, UW-Milwaukee
Assistant GIS Specialist
Cartography and GIS Center - Bolton Hall