I suspect that the stock mission planner may be the source of the problem, and that developers who use self-built mission planners do not experience this issues. Regardless, I believe it would be a significant burden to ask the developer to modify this continually.
For now, I will display the information in English. Thank you. However, I do hope that a modification will be made in the future.
Additionally, I would like to draw your attention to another issue that I believe is more important. : "No SRTM data for this area" on south pacific sea