Yeah, sadly, there are scattered recordings at marp that don't playback. This is primarily because the uploaders do not playback their own recordings before submiting. Editors wil remove them if they find they are unplaybackable. But there's just not enough time to get them all.(posted 9009 days ago)I'll take a look at the nbajam recordings and give them a try. Also, it's not too serious to find recordings that don't playback and are not "confirmed." However if the recording is confirmed (that means the score is orange instead of green) and it doesn't playback, please post a loud message, that means a confirmer might have made a mistake confirming a game that couldn't be played back (or just needs to give more specification on HOW to get it to playback properly).
I noticed none of the nbajam recordings are confirmed yet which means no one with confirming ability was able to get them to playback (either because they couldn't or because they didn't try.)