Hi!
I detected issue with incorrect visualization of PictureMarkerSymbol. Url property is image data encoded in base64. Behavior of this issue undefined.
Condition for search crashed picture: many objects with large sizes, arcgis js api 4.10, 4.11
I created example on jsfiddle https://jsfiddle.net/catcherholms/dmp1z387/136/
Issue visualization I attached.
I had the same issue with this last summer: Feature Layer incorrect rendering with webgl rendering and picture marker symbols and it was resolved with 4.9.
A couple of bug reports were filed about it:
#BUG-000115988 Picture Marker Symbols in Feature Layer are unable to display with WebGL enabled when imageData of the symbol stored at REST Endpoint is lengthy.
#BUG-000115991 Picture marker symbols in FeatureLayer with WebGL enabled display as jumbled when using more than 10 unique value categories to symbolize points.
You may want to open a support ticket with Esri and have them look at this again if you're seeing the same issues because it looks like the exact same thing we were experiencing with 4.8.