Reproduction steps:
1. Open the attached project "CrashRepro"
2. Click on the second crate in the Hierarchy window
3. Click on the action in the NodeCanvas window
4. Copy and paste a few times

Expected result: The Action gets copied
Actual result: Editor crashes

Reproducible with: 6000.0.47f1, 6000.1.0f1, 6000.2.0a9
Couldn’t test with: 2022.3.61f1 (Package is broken)

Reproducible on: Windows 11
Not reproducible on: No other environment tested

Notes:
Step 4 can be other actions, such as adding another action, setting an action, setting string values in the node canvas, or copying and pasting seems to be the fastest way to reproduce the crash
Not a 100% reproduction rate but seems to reproduce within a few minutes

First few lines of stack trace:

{noformat}0x00007FFCA46FAAB0 (Unity) GeneratePropertyDiffInternal
0x00007FFCA46FBD17 (Unity) GeneratePropertyDiffInternal
0x00007FFCA46FA1D7 (Unity) GeneratePropertyDiff
0x00007FFCA47DBD1C (Unity) GenerateUndoAndRedoDiffs
0x00007FFCA47E8BEA (Unity) PropertyUndoManager::Flush{noformat}