On my end, 4 line pastes are painted in 2 distinct parts, with /fupdate enabled. That is, a clipboard paste into my multi-line editbox and hitting enter to send all 4 lines to the channel immediately. With /fupdate at 1 or 100, it's on without apology.
(ö)_/¯ __(ö) \ \__(ö)__/ __(ö)__ ¯\_(ö) / (ö)__ ¯\_(ö)_/¯ __(ö)__
_/¯|¡| \ |¡|¯¯ |¡| \ |¡| / |¡|¯\_ ¯¯|¡| / |¡| \ |¡| /
\~\ /~\/¯ /~\ ¯\/~\ /~/ ¯\/~\ /~\ /~/
_/ /_ _\ _/ \_ \_ _\ \_ /_ /_ _\ _/ _\