Firefox and IE have conflicting default units for columns, so when a user specifies a column width without including the units in wiki markup, columns break when viewed in another browser. 50 wide columns look fine in Firefox but are very narrow in Internet Explorer.

Confluence should be appending a default unit to any column widths, it could for example specify percentages for values under 100 and pixels for any value above 100.

To replicate:

{section} {column:width=50}
h3. Level 3 Heading
# Numbered List Item
# Numbered List Item{column} {column:width=50}
h3. Level 3 Heading
Normal Text{column}{section}