Time Frame Material Test [Sketchfab Bug]

Description

This is made as bug report for Sketchfab. There is bug in Time Frame animations that import only preserves first and last material from list. There was six materials total, one for each face. Every frame has these same materials in same order. Now there is only materials 1 and 6 left, 6 has taken over all the others. There should be Blender file included in additional files