When dealing with Unity, some errors may happen on specific versions or with specific configurations. So please share as many details as possible.
- Full Unity Version
- Scripting Runtime version, Scripting Backend & Api Compatability Level. All of them can be found on the Player Settings (Android tab).https://docs.unity3d.com/2018.2/Documentation/Manual/class-PlayerSettings.html
- OS (Windows or OSX, and their version)
- Android version, if the issue appears on the device itself
- Anything else that may be related
If possible, providing a demo project that reproduces the issue would greatly help and make it much easier for me to track down the issue and speed up the process.