Tatiana, can you low-key explain what this means. I’m having trouble working it out at first glance. 

🙏In a newer edition of a textbook, for example, new exercises may be added and other changes may be done, which may slightly affect teaching/learning when students have different editions in class.

…книги/учебники одного и того же года ИЗДАНИЯ (Sorry)

A mishmash! Uly, thank you very much🙏🤩

👍🏼🤩

WE’ARE all published - a typo?

... were all ...

👍🏼🤩

Irina, I think you were meant to translate this into English, not Runglish.

mishmash isn't the right word for russian разнобой.

"a mess" can be better

Разнобой can definitely be translated as mishmash in English, depending on context.

Разнобой means lack of uniformity, inconsistency, or things being all over the place, out of sync. It’s often used when referring to things being different where they ideally should be aligned — different opinions, sizes, colors, styles, or even timing.

Examples:

У всех разнобой в расписаниях.
Everyone’s schedules are all over the place / a total mishmash.

В оформлении комнаты получился разнобой.
The room’s decor turned out to be a bit of a mishmash.

MESS is only one way to say it — and not the best because we’re talking about a tangle of different editions… that’s a mishmash 😉

What’s unnatural is “If they don't get the books of the same year edition”… that’s not idiomatic. A native speaker would never word it like that.

Татьяна, а ещё точнее - discrepancy

DISCREPANCY is something different: it’s a lack of compatibility between two or more facts or numbers. It doesn’t work here.

If someone counted the textbooks and reported that there are 100, but the invoice says that 110 were delivered, that’s a discrepancy 😉

Uly, your interpretation of разнобой makes total sense and your examples are on the spot. Here’s one more that’s the first to pop into my head whenever I hear the word:
Новобранцы только начали строевую подготовку и маршируют вразнобой.

Ирина, спасибо за внимание к моему вопросу. У нас здесь сложилась традиция - мы не постим переводы на английский без одобрения носителя этого языка. И кстати, носитель АЯ, в свою очередь, сначала постит свои варианты перевода на русский в комментариях. Логично, не правда ли?