Layer stacking Reflectance maps

Can anyone advise the best way to layer stack Parrot Sequoia Multispectral reflectance maps?

I have tried to do it in ERDAS Imagine 2016, but the resulting image displays layers as block colours (Image 1).

The individual band images display fine in ERDAS. Any advice would be greatly appreciated.

I normally use QGIS virtual raster builder. You can see the workflow at the end of this article:https://support.micasense.com/hc/en-us/articles/115000831714-How-to-Process-MicaSense-Sensor-Data-in-Pix4D. Also, you could do the same with ArcMap.