We have been using ArcGIS Online for a number of years now (since Collector Classic was new) with the offline capabilities being a core function of our workflows. We have many webmaps, feature services, hosted view layers and WebApp Builder Apps. Recently, I've started running into problems with webmaps not downloading in Field Maps that always have in the past. After lots of in-house troubleshooting and checking, I believe the problem is to do with differing spatial references amongst layers and webmaps.
You must use the same spatial reference for the map and all cached services in the map, including the basemap and hosted tile layers.
Can someone please clarify for me if this is a new requirement since Field Maps was launched?
Also, does this apply to all layers within a webmap (not sure what is included in the "all cached services" part), or a subset of layers (we really only use hosted feature services and hosted views of those services)?
What if a side loaded .vtpk was created with a different spatial reference?
I've got layers with differing spatial reference layers that seem to have worked fine for a long time, but now I'm having trouble loading new layers into maps and their continued offline capabilities. I suspect things have changed which has made using layers with differing spatial references less functional when an offline enabled map is essential.