Odd problem with spacing using memoir when switching from oneside to twoside

Question

For reasons I won't bore anyone with, I being forced to change my document at the last minute from oneside to twoside using memoir. However, when I do, I suddenly get odd problems with spacing; the title pages have the entire page's text shifted to the bottom, and the last subsection or paragraph in each chapter is moved to the bottom of the page as well (leaving a huge chunk of vertical whitespace between the last and the penultimate paragraph). I'm sorry, I'd like to provide a minimal working example, but I can't come up with one, so I'm just hoping that someone can point me in the direction of general things to check. Here's some possibly relevant code, though it's a long document:

\documentclass[12pt,A4,twoside]{memoir}
\setcounter{errorcontextlines}{30}
\strictpagecheck
\usepackage[sectionbib]{natbib}
\usepackage{chapterbib}
\usepackage{graphicx}
\usepackage{amsthm}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{authblk}
\usepackage{multirow}
\usepackage{memhfixc}
\usepackage[draft]{hyperref}
\usepackage{lscape}
\usepackage[T1]{fontenc}
\bibpunct[, ]{(}{)}{;}{a}{}{;} 


\setlrmarginsandblock{4cm}{3cm}{*}
\setulmarginsandblock{4cm}{3cm}{*}
\checkandfixthelayout
\fixpdflayout

\makepagestyle{mystyle}
\makeoddhead{mystyle}{}{}{\thepage}
\makeevenhead{mystyle}{\thepage}{}{}
\pagestyle{mystyle}

...

\cleartooddpage[\thispagestyle{empty}]
\include{foreword}
\pagestyle{plain}
\mainmatter
\cleartooddpage[\thispagestyle{empty}]
\include{chap1}

... 

and so on.

Answer 1

Quoted from the memoir documentation (p 5):

When the twoside or twocolumn option is selected then typesetting is done with \flushbottom, otherwise it is done with \raggedbottom.

When \raggedbottom is in effect LaTeX makes little attempt to keep a constant height for the typeblock; pages may run short.

When \flushbottom is in effect LaTeX ensures that the typeblock on each page is a constant height, except when a page break is deliberately introduced when the page might run short. In order to maintain a constant height it may stretch or shrink some vertical spaces (e.g., between paragraphs, around headings or around floats or other inserts like displayed maths). This may have a deleterious effect on the color of some pages. If you get too many strung out pages with \flushbottom you may want to put \raggedbottom in the preamble.

As such, use \raggedbottom to avoid flushing text flush with the lower part of the text block.