I can reproduce this problem by having a string containing valid HTML, and with two of the offending tags in a row. Example:
vStr := '<html><head></head><body>Hi Michael' +
'<br><br>This line will not appear.' +
'</body></html>';
WPRT.Clear;
WPRT.AsWebpage := [wpFormatAsWebpage];
WPRT.LoadFromString(vStr, 'HTML')
I can (hopefully, temporarily) solve the problem by doing a global replace of '<br' with ' <br'.
Am I doing something wrong ?