Translation `wp_sprintf_l()` not synced

The translation process is not something I’m intimately familiar with, but AFAIK the sync is very accurate but the frequency is erratic. Changes in core strings show up in the translation site as needing updating, but it’s up to volunteers to actually do the change. Depending on the language, it could take a while.

Specifically about the wp_sprintf_l() placeholders, it looks like the argument numbering in the revision you linked has been reverted. They do not exist in current 4.9 core code, so we cannot expect the translation with argument numbering to occur at all at this time.
https://core.trac.ww.wp.xz.cn/browser/tags/4.9/src/wp-includes/formatting.php?marks=4503-4508#L4482