First, it should be noted that some versions, such as the two quoted here, have "Sabbath" in the singular, while others, such as the KJV and the NKJV, have it in the plural. This should, to the attentive reader, first raise the question of the text. Are there some Greek texts that read "sabbaths" while others read "sabbath"? A quick check of the standard critical Greek texts shows that there are no variations on that word, that in fact it is in the plural. So the follow-up question is why some translations have translated it as a singular. This becomes a more difficult issue, and demonstrates for us that while it is necessary that interpreters of the Bible be able to read it in the original languages, that in itself does not necessarily solve difficult questions. In fact, sometimes it seems to increase the difficulty of the question.
In this case, the increased difficulty comes from the following set of facts. First, the Greek word 'sabbaton" occurs sixty some-odd times in the New Testament. In over forty of these, the word is in the singular, while in the remaining cases it is in the plural. But both singular and plural forms are used with singular meaning. For example, in Mt 12:1-12, the word occurs eight times, three times in the singular (vss. 2, 5, 8) and the other five times in the plural (vss. 1, 5, 10, 11, 12). Yet most versions translate all eight of these occurrences in the singular.
Further, on a number of occasions, 'sabbaton' means "week," as it does in 1 Cor 16.2. Yet even here, the usage is inconsistent. In 1 Cor 16:2 the word is singular, whereas in Lk 24:1 it is plural.
So rather than immediately solving the problem by reference to the original language, I seem to have complicated the issue. Therefore, more posts will be necessary.