Currently Section Translation application supports multiple target languages for development environments without refreshing the page.
However, in production environments supporting multiple target languages would require redirecting to the corresponding target wiki so that the translation can be successfully published.
Change 722829 had a related patch set uploaded (by Nik Gkountas; author: Nik Gkountas):
[mediawiki/extensions/ContentTranslation@master] SX: Add redirection to target wiki on target language change
Change 722829 merged by jenkins-bot:
[mediawiki/extensions/ContentTranslation@master] SX: Add redirection to target wiki on target language change
Checked that the expected behaviours occur in each case:
I wonder if a better strategy would have been to do the redirect in the transition to the editor (i.e., after clicking "start" translation).
In this way, some of the reloading and transition glitches could have been avoided. I don't know whether this approach was considered when the ticket was created, but we can reconsider this for the future if we observe issues with the current approach.