UIView mysteriously expand by 1 pix when added to as subview

I created a开发者_StackOverflow社区 custom "component" made up of UIView and it gets added as subview on any visible view. What I found strange is that when it get added to a view the second time, the width got increased by 1 pix. This caused a problem when it expanded the background image and causes the image to blur out.

Any ideas why a view will get expanded (or shrink) when added to another view?

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The issue may be related to the location of the view. Perhaps one of these stories will shed more light on the issue:

Fixing Blurry Subviews

Why does a PNG image sometimes get blurry depending on its position in a view