The behavior AQ mentioned is similar, but not quite the same. In the LabVIEW 2019 f2 patch, we addressed Bug 188376 (CAR 742093). That Bug resulted in a crash when probing class wires that included maps in the object's data. I've reproduced the behavior you're seeing in LabVIEW 2019 SP1. I filed Bug 966521 to get that on our radar. As a quick note, I did test LabVIEW 2019 and the behavior isn't there. If you need to debug, you can do so on a patched 2019 installation.