I believe it's all about how fast your node catches up with the rest of the network. The confirmation of your transaction actually depends on if it has been included in a block and not just it sitting in the mempool. Remember that your node actually has to download and fully validate that new block containing your transaction before it can officially update its status to confirmed. So there's  actually a very high chance that what what you're seeing is a temporary lag in synchronization.

Your pruned node should  be working  fine since it could correctly identify the transaction in the mempool but is waiting to process the block itself to reflect that it. is now confirmed. Check your network speed because sometimes it can contribute to this lag too.