In the document I’m working on are several object bottom aligned. Therefore the (two-column) text is also bottom aligned. If I Span the first sentence the hole story shifts slightly and disturbs the layout. This picture https://adobe.ly/1Je1fkb illustrates the problem.
Yes, that happens for me, too. Wow, I don’t remember seeing that before. That is interesting. May be a bug! I don’t see any way around it, except using align to baseline grid.