I'm still learning here so perhaps I'm making a basic mistake but I'm really confused.

I've opened a folder in LRTimelapse with three keyframes and taken it into Lightroom. As a test I've made no edits but have synced the key frames and saved metadata as in the instructions. Now when I reload in LRTimelapse it introduces a gradual ramping of the white balance and tint through the sequence of shots. The camera was recording raw files all with a preset 4700k white balance.

What is happening? Many thanks.

Could you please check if the Whitebalance is the same on all 3 keyframes in Lightroom?
Also make sure that you saved Metadata from the Grid View (G) - if you do it from Deveop Module, Lightroom will only save the metadata for the current image and you will get exactly what you are experiencing.
Solution: Do the save Metadata again in Lightroom, this time from Grid View. Now change to LRTimelapse, Reload. Check the WB Values for the keyframes. Do the Auto Transition. Now the Keyframe column in the Table should disappear, because all values are equal.

If the problems persist: Which camera is that? Which file format?

Exactly right, I had saved metadata in develop mode.
All good now.
Sorry my fault, not reading instructions properly!
Many thanks.