I've noticed something strange lately with the command
gnus-uu-mark-all (M-P a)

Certain messages do not get marked anymore.
Recently I removed  (standard-display-european 1) from site-start.el
because it seemed to be causing emacs to see multibyte chars as UTF-8.
Since removing it... The different behavior of `M-P a' showed up.
Put it back in, and M-P a marks the same messages it missed.

gnus-uu-mark-buffer (M-P b) does the job with or without
(standard-display-european 1).

Anyone know what is happening here?

Below are two sections.  First section shows a summary line taken
from summary  buffer with (standard-display-european 1) in init files.

This same line is missed with (standard-display-european 1) removed
The data below `=====' is gotten by placing cursor on one of the
subject chars and pressing C-u C-x =:
The double ===== marks the second section where I did the same thing
on two summary lines with (standard-display-european 1) removed. 

=============================================================
=============================================================
Section 1:

1 line from summary buffer:   
    1O# 08-May [  15: ÷ë                  ] »Ú½§òÊþØ·»ô20ª
========================================================
  character: ° (0260, 176, 0xb0)
    charset: eight-bit-graphic (8-bit graphic char (0xA0..0xFF))
 code point: 176
     syntax:   	which means: whitespace
   category:
buffer code: 0xB0
  file code: not encodable by coding system iso-latin-1
  font: -Adobe-Courier-Bold-R-Normal--14-100-100-100-M-90-ISO8859-1

There are text properties here:
  gnus-number          97
  face                 gnus-summary-normal-ancient-face

====================================================================
====================================================================
Section 2 

With  (standard-display-european 1) commented out

Two from summary buffer