File update deletes translation?

Uploaded few marketing files into Crowdin, run the translation by deepL translate, update a file and half of translations are lost. In activity says that I deleted 90 stings and uploaded 90 stings. But I changed only 2 stings. How is this possible?

Probably those files are not key based. If they arent key based - its expected. You change some sentence in the middle of file - all other that are stored after that middle one received a new internal id and system see them as a new one.

If you work with .json or other key-based format this will not happen. If not key based files you need to run pre translation all the time. Or use duplicates/branches.