It shouldn't.
I had an SQ award BNE-SIN-CNX and wanted to change it to BNE-SIN-HKG and was told that I had to pay a change fee as the destination has changed but I will also get back some fuel surcharges. Turns out I received a refund of ~AUD60 a few days later.
So not sure why any refund should take 6-8 weeks unless the airline wanted to keep the money longer.
Totally correct. A bit like how WoW has negative working capital. They pay many suppliers generally after 90 days but get the money within a few days at most at point of sale. Also many Govt departments (at all levels - Fed, State & Local) do it. I think it was 2 budgets back (maybe 3) it was a "Budget Measure" for the Fed Govt.
They were going to 'stimulate the economy' by encouraging Fed Govt Departments to pay earlier than max possible period. One 'analyst' suggested they should really "stimulate the economy" by encouraging the Victorian State Govt to also extend the time for traffic fines to be paid given his speeding back from the 'lock-up' to be first to market with his company's budget analysis.
Strangely enough, the Victorian State Govt did not oblige.