Win10 / GTX 1070
Short description of error
I'm not sure we can consider it as a bug, but the layout alignment doesn't seems to be correct in all situations.
A simple example with row and column can show what seems wrong.
layout = self.layout
col = layout.column(align=True)
row = col.row(align=True)
Exact steps for others to reproduce the error
Run the script in the attached .blend file and check the result in the sequencer panel.