ID 231443 - The ModifyMetaData node crashes Nuke on exit if it is part of a group

Problem summary
When a group is created with the 'ModifyMetaData' node, Nuke crashes on exit.

Customer reported version
nuke.10.0v4

Customer reported platform

- Fedora 18 x86_64 kernel version 3.10.14-100.fc18

- CentOS 7.2.1511 x86_64 kernel version 3.10.0-327.3.1.el7

Steps to reproduce

1) Open Nuke and add a 'ModifyMetaData' node to the DAG or open the attached Nuke script (metadata_crash.nk)

2) Select the node and create a group

3) add metadata node as a user knob to the group
4) Exit Nuke...crash...

Workaround
Unknown. 

Reproduced by support
Reproduced by Support only in Nuke 10.0v3 and 10.0v4 
Windows 7, OSX 10.10.4

Expected behaviour
No crash when closing Nuke

Actual behaviour
Nuke crashes when closed