The target for the "Should be Loaded" variable appears to have change to "Level Streaming Kismet". This means that it no longer works with the "Get streaming level" node and can cause errors when used in a project that is upgraded from 4.19 to 4.20.
Does not occur before 4.20
Result: The node does not show up in the list as it is now looking for a Level streaming kismet object reference rather than a level streaming object reference
Expected: The variable would be available for use with the "Get Streaming level" node
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-60924 in the post.