Steps to reproduce:
1. Open the attached project ("1210259.zip")
2. Open the "Game" Scene
3. Select the "Overworld" GameObject in the Hierarchy
4. Right-click the "Rect Offset" field and select "Copy"
5. Right-click the same field again and select "Paste"

Reproducible with: 2019.2.18f1, 2019.3.0a11
Not reproducible with: 2019.3.0a12, 2020.1.0a18
Couldn't test 2018.4 due to Odin errors

First 5 lines of the stacktrace:
0x00007FF719C0CD31 (Unity) TransferField_NonArray<StreamedBinaryWrite,Converter_SimpleNativeClass<RectOffset> >
0x00007FF719C2AAD7 (Unity) Transfer_SimpleNativeClass<StreamedBinaryWrite,RectOffset,0>
0x00007FF71844B582 (Unity) ExecuteSerializationCommands<RemapPPtrTransfer>
0x00007FF718456011 (Unity) TransferScriptingObject<StreamedBinaryWrite>
0x00007FF718452A00 (Unity) SerializableManagedRefTransfer::Transfer<SerializableManagedRefBackupGenerator>

Note:
- Doesn't crash in the newer versions, instead throws an Argument Exception from Odin's side when trying to inspect the script containing the RectOffset