Hi yurloc and welcome to the forum!
Could you give some examples on items which are translated in build17 but not on Launchpad? Translations on LP are added to trunk from time to time and when trunk is released as an official build that is based on the current state of translations. Therefore it seems odd that build17 would contain translations which are missing from trunk, but several things might have happened since build17 was released:
- The string has changed in some way, either to improve wording or fix typos. In these cases, the string will appear as a new one and will need to be translated.
- It is possible to remove translations (can be done in case someone thinks it is a poor translation and it will be more confusing than displaying the original string)
It would be nice to have some examples so we can take a look and see whether it is the old string or if it has changed somehow during the current development cycle.
Also; thanks for helping out translating WL. You may want to check or compare with the development version instead though, since a lot of text has been added or changed since build17 was released.