To address the issue of Spine crashing on certain Android devices when using Unity Timeline, it is important to ensure that you are using the latest version of the spine-unity runtime. Since you are using version 4.1, consider updating to the latest 4.2 version, as it may contain bug fixes that could resolve the issue. Additionally, it would be helpful to gather more detailed logs and stack traces from the affected devices to better understand the cause of the crash. If the problem persists, you might want to create a minimal Unity project that reproduces the issue and send it to Esoteric Software for further investigation.

@Midial Sorry to hear you're having troubles. Please note that the 4.1 unitypackage you're using (2024-02-26) is not the latest available (2024-06-19). When encountering issues, please always check first whether the latest package fixes your issue:
https://esotericsoftware.com/spine-unity-download#Older-Versions

If it does not resolve the issue:
My best guess for your above out-of-range array access to happen is if the loaded (binary) skeleton format does not match your spine-unity runtime version. So i.e. the exported skeleton data file is of an older or newer version than your runtime supports. Have you perhaps modified the spine-unity runtime code, and i.e. changed any of the version checks?

If you can't reproduce this issue locally, are you perhaps using any download mechanism like Addressables, Asset Bundles or the like? If so, please make sure that there are no outdated download packages left which might be loaded accidentally instead of the correct package.

@Midial Sorry to hear that. If the issue persisted with the latest Spine 4.2 Editor version, could you please create a minimal Unity project which still shows this issue? You can send it as a zip package to contact@esotericsoftware.com, briefly mentioning this forum thread URL so that we know the context. Then we can have a look at it.