I’ve been having this issue ever since I completed the two 2.4 hr races last month. I saved the replays from both events, but whenever I try to share them it either fails to do so, or tells me right away that I don’t have enough slots available.
Well, I clearly have enough slots because I only have about 5 or so shared replays. I even unshared a few and still it tells me I don’t have enough slots. Shorter replays that I have still share just fine.
From my experience, the game only saves about 30 mins of the replay and stops recording after that, but it still doesn’t explain why it won’t share. Maybe it really is just too long? I’m not sure.