For me, it's too much water and moisture.Leave it a moment with minimal watering.

It was not useful to amend when you plant a new camellia. It has usually enough fertilizer. If it's possible (controlled release fertilizer), keep it out and wait.

Laurie

Here is a link that might be useful: lovcam.org

Thank you, Laurie.
I will keep watching.

Ha Xuan

There is a time of adjustment during transplant. It could be weather, water, soil or any other disturbances. If you ground condition is good, no strong wind, not too wet or too tight soil, or not too much sunlight etc. The plant will later revover and establish better than container planting.

Try not to use manure, it might contain excessive salt. Try to use only minimum amount or no fertilizer first growth season, so root want to reach out more branches.
Hope for the best.