u/Alternative-Heron-71

I am someone teaching myself Latin in Korea. I’ve encountered a problem I can't find the answer to, so I am reaching out here for help.

>Īnfēsta tibi erit terra, quae bibit sanguinem Abēlis: cum colueris eam longō et dūrō labōre, nūllōs feret frūctūs.

This sentence is from Chapter 10 of 『Epitome Historiae Sacrae』. In the textbook, there is a note regarding "cum colueris" stating that it is in the perfect subjunctive and is equivalent to 'quamquam colueris (fut perf).'

However, I don't quite understand why [cum + perfect subjunctive] is being used here with the meaning of the future perfect indicative. Is this due to a rule of sequence of tenses that I'm unaware of?