Funds being delayed

I’ve sold hundreds of items through this amazing platform. Great app for trading/selling. I’m kind of concerned and confused on why my funds from a previous transaction are in a delay. I’ve never had this issue. Also confused despite on the delay, due to my reputation on here being so high. Also the buyer that recently purchased from me has a ongoing occurance with Great reviews and nearly at a hundred. Any answers? Is someone here to help me better understand the delay? Thanks guys!