As Naresh correctly reminded me, this problem stems from the issue described in bug 799378, so let's make this new one a duplicate. For what it's worth, bug 799378 mentions another common case where this occurs (with leads rather than email templates) and a workaround when writing custom modules that have this issue.
As Naresh correctly reminded me, this problem stems from the issue described in bug 799378, so let's make this new one a duplicate. For what it's worth, bug 799378 mentions another common case where this occurs (with leads rather than email templates) and a workaround when writing custom modules that have this issue.