Arbitrary Warning Spamming of "AnimationTrack limit of 256 tracks for one Animator exceeded, new animations will not be played."

Bug Reports Engine Bugs
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#1

VIDEO: https://streamable.com/5kf14g

I created a custom humanoid rig (R17) and am encountering a strange bug after spamming movement keys for approximately 1 minute. After doing so the warning “AnimationTrack limit of 256 tracks for one Animator exceeded, new animations will not be played.” will begin to spam itself towards infinity at what appears to be once per frame. This quickly reduces the framerate to zero and crashes the session if the humanoid’s animator is not quickly deleted. This bug occurs EVERY play test under these conditions.

I have ensured no plugin or other outside code is interfering.

EDIT: Jumping is not necessary to produce the bug, movement spam will result in it.
EDIT 2: The warnings are coming from the client, not the server. Studio Networking “Show Active Animation Asset” also shows no irregularities.

EDIT POTENTIAL CAUSE IDENTIFIED: Parenting the Motor6Ds to their Part1 stops the warnings from appearing. There is no logical reason this should affect the behavior, yet it seems to be the case.

Failed Mitigation Attempts:

At first I thought this might be a bug with ROBLOX’s default Animate script improperly loading AnimationTracks, however, this does not appear to be the case. I closely monitored all loaded tracks and even made my own custom Animate script to ensure proper caching which made no difference. I then thought it might be related to the in-built Jump behavior, but using a custom velocity-based jump made no difference. Monitoring Animator:GetPlayingAnimationTracks() clearly shows that never more than the few expected animations are playing on both the client and server. It would be helpful if it were possible to monitor LoadedTracks directly (GetLoadedAnimationTracks() should exist…), but regardless I’ve isolated every variable I can imagine outside the engine to no avail. Disabling ClientAnimationThrottling or PreferLodEnabled also made no difference. Using my own custom animations made no difference.

I am truly at a loss for what could be causing this other than an engine bug. Everything is fine up until the warnings start spamming.

I wonder if it might be related to client to server animation replication. Further testing is necessary. The bug still occurs with a server-sided animation script.

Steps to Reproduce:

  1. Create new place
  2. Insert StarterCharacter.rbxm (26.9 KB) in StarterPlayer
  3. Play Test, spam movement keys for approximately 1 minute, monitor the output.
6 Likes
#2

Thanks for the report! I filed a ticket in our internal database and we’ll follow up when we have an update for you.

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