Could you please tell me what Xibo version are you using please?
Quick flash when the layout reloads (when the region with the longest duration ends), will always occur, although it certainly should not take even a full second not to mention more than that.
You can also make sure that background image (if exists) is in .jpg format, the background colour should most likely be black (preference).
Perhaps also double check that you have IE installed there with correct entries for browser emulation and you can also try GPU_RENDERING registry entry.
Xibo for Android certainly allows for more in many aspects, perhaps you could convince your company/it team to do so testing with android clients? Just in case, here are our recommended devices - Recommended Android Hardware
It’s also possible to use on-premise (offline) licencing module for Xibo for Android to licence your android devices in case when the internet access would not be allowed at all on the device.