Description:
------------
When I run short script below I every time receive different values in output. It may print 7 and may print 11. PHP-file has encoding cp-1251.

Here's version info from my webserver

-bash-2.05b$ /usr/sbin/httpd -V
Server version: Apache/2.0.63
Server built: Jul 22 2008 23:09:16
Architecture: 32-bit
Server compiled with....
-D APACHE_MPM_DIR="server/mpm/prefork"
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D HTTPD_ROOT="/usr/local/apache"
-D SUEXEC_BIN="/usr/local/apache/bin/suexec"
-D DEFAULT_PIDLOG="logs/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_LOCKFILE="logs/accept.lock"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="conf/mime.types"
-D SERVER_CONFIG_FILE="conf/httpd.conf"

Reproduce code:
---------------
<?php
print(strpos('&#1074;&#1072;&#1089;&#1103;12hello[b]','[b]'));
?>

it contains cyrillic characters. If I replace them with latin ones everything works fine

Expected result:
----------------
I expect 11 to be printed

Actual result:
--------------
Actual results is sometimes 11 and sometimes 7. 7 looks like cyrillic characters are simply omitted during calculation.