I've run into a weird problem that I can't find described anywhere else online:
I loaded a point shapefile into my map document. Then, I set a layer definition query - this resulted in the layer displaying 199 features from the shapefile. I did not save a .lyr file, I was just using the layer in one map document's data frame.
Next: I try to load that same shapefile into a different dataframe in the same map document, but only 199 features show up. I check the layer definition query in the new dataframe and there isn't one. I try to re-load the shapefile, still only 199 features. I closed the map document, Arc, restarted my computer, loaded the shapefile in QGIS, etc. - no matter what, there's only 199 features matching the initial layer query I used.
Ultimately: I have a shapefile at the original file location but it is not the same shapefile - it now only contains the data that matched the layer definition query I set before.
I don't know when this happened specifically, unfortunately. I definitely never opened an editing session on the layer with the query, nor did I use field calculator outside of a session.
Has anyone had an experience where Arc randomly modified the source dataset like this, or know how this may have happened?