Hi there!
Here is how to reproduce the problem:
Map 1 sequence file in the diffuse texture with a Corona material
Apply on object
Show shaded material in viewport
It is animated when we scrub the timeline
But when we create a viewport preview, the texture is not animated
With a standard max material, it works.
I have:
3dsmax 2015 sp4
quadro k5000
Corona version: 1.6 DailyBuild Apr 7 2017
Thanks!