Unlinking sub-project breaks predecessor and successor link

[Bob Hillier]

In my simplified example, I have a Master / subproject schedule. The subproject has a single task finish-to-start dependency with a task in the master schedule. The subproject is a Linked subproject (i.e. a separate file). All is good.
Next, I want to combine the subproject with the master project in a single file. I open task information dialog of the subproject and, on the Advanced tab, uncheck the Link to Project box and click OK.
The successor link from the subproject to master disappears. 🙁
However, the predecessor link from the master to the subproject remains (but still has the qualified pathname of the subproject). Problem is the task ID refers to the task ID in the Liked file (e.g. task id in the separate subproject) and not the new task id in the unlinked, newly inserted subproject. (Did I explain that correctly?)
Net result, the predecessor and successor links are no longer valid.

What am I doing wrong here?

My real life master / subproject schedule involves 7 subprojects and a total of 2932 tasks. I’ve been asked to prepare a single file and need the predecessor and successor links to be correctly updated. Is there a solution?

Suggestions and direction are welcome.

MS Project Professional 2013

Bob

[Author]

Posts