Power Automate, calling child flow Bad Request Error

Problem: When I call a child flow that uses a connection, the parent calling flow receives the error "Bad Request" with the following details "Action 'Run_Child_Flow' failed: Failed to parse invoker connections from trigger 'manual' outputs. Exception: Could not find property 'headers.X-MS-APIM-Tokens' in the trigger outputs. Workflow has connection references '["shared_wordonlinebusiness","shared_sharepointonline"]' with invoker runtime source.". 

Error shows in the parent flow runs.

Initial Hypothesis: Reading the message originally to me suggested that permissions are being lost between the parent and child flows.  I did some Googleing/copiloting to see if anyone had seen the issue before and Darren Lutchner has a video that explains the issue and fixes it perfectly (https://www.youtube.com/watch?v=Yuh3Nlf9wrs).  

Resolution: Watch Darren's video for a great walkthrough to understand the issue fully. 

Resolution Summary:

1. Go to the "Child Flow", Edit the "Run only users"

2. I had two connections: Word Online (Business) & SharePoint, change them both from "Provided by run-only user" to "Use this connection (...)".  Save and the parent flow starts working and calls the child flow correctly.