Our group has a habit of casting spells in the morning before ending our long rest, to use unused spell slots, we call it "casting down" spells. Typcial spells we cast are those with longer durations like mage armor and aid to buff us for the upcoming day without consuming any of the coming day's fresh spell slots. We also use it for divination spells like scrying.
I mentioned this in a recent exchange about the merits of aid, which I think is a great spell as it can be upcast to give party members 15-20 temporary hits in this way, and was told this was shenaniganry, which made me think: is what we do in any way not conformant with the rules? Is it unsavory?
Looking at the long rest definition, it states (PHB p. 186):
A long rest is a period of extended downtime, at least 8 hours long, during which a character sleeps for at least 6 hours and performs no more than 2 hours of light activity, such as reading, talking, eating, or standing watch. If the rest is interrupted by a period of strenuous activity – at least 1 hour of walking, fighting, casting spells, or similar adventuring activity – the characters must begin the rest again to gain any benefit from it.
So as far as I can see it is entirely legit to sleep for six hours, maybe hold watch for 2 hours sometime in between, and in the morning before officially ending the long rest, cast spells for less then one hour, then resume the rest and end the rest at which time spell slots are regained.
If casting spells during a long rest is technically possible has also been answered here, with yes. But is doing that at the end of a long rest purely exploiting a technical loophole in the rules or can it be a legitimate use of rules from a narrative perspective, for the characters in-game?
Am I missing something?