If you:

• create a select-list custom field
• save a search involving just that custom field
• subscribe to the saved search, with your email preference set to HTML

Then JIRA fails to send the mails, and in the logs one gets the following error on every send attempt:

2004-12-09 17:35:51,536 ERROR [velocity] Method getDescription threw exception for reference $SRUtils in template templates/email/html/filtersubscription.vm at [22,17]
2004-12-09 17:35:51,537 ERROR [com.atlassian.velocity.DefaultVelocityManager] Exception getting message body from Velocity: org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getDescription' in class com.atlassian.jira.issue.search.SearchRequestUtils threw exception class java.lang.NullPointerException : null
org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getDescription' in class com.atlassian.jira.issue.search.SearchRequestUtils threw exception class java.lang.NullPointerException : null
at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:246)
at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175)
at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:220)
at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:55)
at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:166)
at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:114)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
at org.apache.velocity.Template.merge(Template.java:256)
at org.apache.velocity.app.VelocityEngine.mergeTemplate(VelocityEngine.java:450)
at com.atlassian.velocity.DefaultVelocityManager.getEncodedBody(DefaultVelocityManager.java:97)
at com.atlassian.jira.mail.MailingListCompiler.sendLists(MailingListCompiler.java:142)
at com.atlassian.jira.mail.MailingListCompiler.sendLists(MailingListCompiler.java:106)
at com.atlassian.jira.mail.SubscriptionMailQueueItem.sendSearchRequestEmail(SubscriptionMailQueueItem.java:87)
at com.atlassian.jira.mail.SubscriptionMailQueueItem.send(SubscriptionMailQueueItem.java:69)
at com.atlassian.mail.queue.MailQueueImpl.sendBuffer(MailQueueImpl.java:55)
at com.atlassian.jira.service.services.mail.MailQueueService.run(MailQueueService.java:23)
at com.atlassian.jira.service.JiraServiceContainer.run(JiraServiceContainer.java:53)
at com.atlassian.jira.service.ServiceRunner.execute(ServiceRunner.java:50)
at org.quartz.core.JobRunShell.run(JobRunShell.java:147)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:387)