When I create and edit multiple key frames in Lightroom and save the metadata to files the WB data is not being transferred to LRTimelapse Pro 6.1.2. When I hit the auto transition button the key frames momentarily display question marks for the WB temp and tint and then it defaults values that I did not choose nor were reflected by the "as shot" images.

I have tried going to the Menu tab "Metadata" and selected " Define White Balance Handling", but neither of the two options does anything to solve the problem.

Has anyone come across this problem previously?

First of all you should always start the workflow in LRTimelapse, and not Lightroom.
LRT does important initializations that might also be important for what you are experiencing.
Try starting the workflow again by removing the sequence from Lightroom and doing "Metadata / Initialize" in LRTimelapse. Then Start the workflow from left to right.

If the problem persist it might be due to the outdated Lightroom Version that you are using. I'm trying to maintain compatilibilty with LR 6, but officially LRTimelapse 6 requires Lightroom Classic. That's because I cannot test it anymore because I don't have it.
I'd really recommend you to upgrade to LR Classic, it's so much faster and the new Masks features alone are so great that it's worth upgrading. Also you'll have the best compatibiliy with LRTimelapse.