ShardBar texture issue

[Aprikot]

The ShardBarFrameShard background textures appear to accept SetGradientAlpha() only if their frame slot has no active shard, whereas they will accept SetVertexColor() shard or not.

The textures:

select(5,ShardBarFrameShard1:GetRegions()),
select(5,ShardBarFrameShard2:GetRegions()),
select(5,ShardBarFrameShard3:GetRegions()),

The effect:


This has me stumped...wondering if anyone can shed any light. Thanks.