We had not included all the passports/travel docs in the app - no issues came up when we 'added.'
And yes, I didn't bother doing the spanish ones (because, well, give me a break), and the remaining ones were also Cyrillic. The Russian and other countries in Europe using Cyrillic stamps (that I know of anyway) use the Euro standard of a small rectangle with name of the port of entry and then dates with an arrow for entry/exit and I think an image for type of port of entry (plane/train/ship anyway). So basically what would I be translating? The name of the port of entry?
There may have been a couple of stamps with Arabic as well as English, but repeating what was there in English.
Anyway: yes, we're supposed to translate everything. But sorry, would have been stupid. (IMO, YMMV)