Hi Evan,
I worked on a MacBook Pro 8 GB, with MacOS Mojave v 10.14.3. and tested with Safari Version 12.0.3 (14606.4.5).
Screen1 of my small project has 8 event handlers, 7 procedures and 21 variables. With all blocks expanded.
Right click/Download blocks: MIT AI2 prod and test with Safari gives attached messages but Chrome downloads them.
The above results are the same for my big project with 150 event handlers and procedures and around 240 variables.
Noel