Template markup error message in Internet Explorer 8

When debug mode is turned off and during template changes administrator mistyped tag name or something like this, then descriptive error message (text on yellow background with red border) is shown with instructions how to fix given error.

Together with an error "500" header is sent. It has no side effect in Firefox, but in Internet Explorer 8 this header prevents mentioned above descriptive message from appearing. In this cases Internet Explorer 8 shows his default error message screen.