As others have posted, ColdFusion 8.0.1 Cumulative Hot Fix 3 (CHF3) was released today. This hot fix contains a lot of new fixes, but I've been waiting for is this one:
Fix for the error "Cannot find CFML template for custom tag" thrown under load when using THIS.customtagpath in Application.cfc and "enable per app settings" is enabled.
In my testing before this hot fix I would see this error in about 8-10% of requests, even under what I would consider light load. After applying the hot fix and running the same JMeter tests I wasn't able to reproduce the issue.
Be sure to check the TechNote for a complete list of what's fixed in this release.