Thanks for the extra info,
I did a google search for ‘unreal engine android panner’ and came across this thread which mentions adding extra ‘customized UV channels’ to the Material (Click on the ‘Result’ node in the material to see these options).
Also in this Mobile Materials Doc The Solution listed for "Material Animation with Time Expressions looks choppy but framerate is good elsewhere." says Make sure the Period property is enabled in the Time expression along with a Period. This will move the computation to the CPU and run at full-precision instead of half.
Plus in the Material there is an option “Mobile → Use Full Precision”. (Try this first)
Please let us know if/which one of these 3 methods fixes it for you.
PS, I’m moving this from ‘Programming & Scripting’ to the ‘XR’ section.