I had a null reference in TMPro that I thought was Editor-only, so I decided to postpone looking into it, but it just popped up in a standalone build. Callstack: IndexOutOfRangeException: Index was outside the bounds of the array. at TMPro.TMP_Text.FillSpriteVertexBuffers (System.Int32 i, System.Int32 index_X4) [0x00017] in <ffe6991d8ff94aa89c869994eb65ae17>:0 at TMPro.TextMeshProUGUI.GenerateTextMesh () [0x05756] in <ffe6991d8ff94aa89c869994eb65ae17>:0 at TMPro.TextMeshProUGUI.OnPreRenderCanvas () [0x0012c] in <ffe6991d8ff94aa89c869994eb65ae17>:0 at TMPro.TextMeshProUGUI.ForceMeshUpdate (System.Boolean ignoreActiveState, System.Boolean forceTextReparsing) [0x0003a] in <ffe6991d8ff94aa89c869994eb65ae17>:0 at TeletypeTMPro+<TeletypeSequence>d__26.MoveNext () [0x000f4] in <d9cd6f83201849859074223644d8dfb6>:0 at UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) [0x00026] in <e3cc0d511c49480aba0b4b05faed2ad3>:0 The code in TMP_Text.cs that causes it, with an out of bounds materialIndex: Code (CSharp): int materialIndex = m_textInfo.characterInfo[i].materialReferenceIndex; index_X4 = m_textInfo.meshInfo[materialIndex].vertexCount; The way I am able to get it to reproduce consistently in my project (which is uploaded to Unity per our other thread, Stephan) is to go into prefab mode on UI tooltip - item, then click on something like item primary stats in the hierarchy and change its font material's face color. Lots of other things trigger it as well. I added some bounds-checking to that area of TMP_Text.cs (as well as to the two other places in that file with similar code), and I get messages that look like this, after materialIndex is obtained: materialIndex 3 but only have 3 mesh infos I am seemingly able to suppress this, but I'm not sure if there's something wrong with my prefab itself that I should also fix. Thank you.