png4ie plugin sporadically serving up alternate content in FF

I decided to try the png4ie plugin but I’m now seeing some odd behavior.

For some reason, within one of my templates, the plugin is serving up to Firefox the alternate content intended for IE.

Below is this tag I have defined in my template:

a href="/home/">{exp:png4ie}full_path_to_image/logo_interior.png{/exp:png4ie}</a>

This is what is rendered in FF:

<a href="/home/">http://www.fashiondiner.com/themes/site_themes/fashiondiner/spacer.png

Which will not work, obviously, because it’s tapping into the AlphaImageLoader filter for IE.

I’ve been trying to optimize this site by enabling certain caching features. This is when I began to notice this situation. Currently, I have no caching features enabled but this trouble still persists. If I clear EE’s system cache, I will get the image back. But this problem seems to re-occur for no apparent reason as I’ve gone thru this process several times.

Any idea on where to look?

ExpressionEngine 1.6.2 Build: 20080206

Moderator’s note: Moved to the Plugins subforum.