Could it be due to caching settings in htaccess which were meant to speed site up?
## EXPIRES CACHING ##
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access 1 week"
ExpiresByType image/jpeg "access 1 week"
ExpiresByType image/gif "access 1 week"
ExpiresByType image/png "access 1 week"
ExpiresByType text/css "access 1 week"
ExpiresByType text/html "access 1 week"
ExpiresByType application/pdf "access 1 week"
ExpiresByType text/x-javascript "access 1 week"
ExpiresByType application/x-shockwave-flash "access 1 week"
ExpiresByType image/x-icon "access 1 week"
ExpiresDefault "access 1 week"
</IfModule>
## EXPIRES CACHING ##
# BEGIN Cache-Control Headers
<ifModule mod_headers.c>
Header set Connection keep-alive
<filesMatch "\.(ico|jpe?g|png|gif|swf)$">
Header set Cache-Control "max-age=2592000, public"
</filesMatch>
<filesMatch "\.(css)$">
Header set Cache-Control "max-age=604800, public"
</filesMatch>
<filesMatch "\.(js)$">
Header set Cache-Control "max-age=216000, private"
</filesMatch>
<filesMatch "\.(x?html?|php)$">
Header set Cache-Control "max-age=600, private, must-revalidate"
</filesMatch>
</ifModule>
# END Cache-Control Headers
<ifModule mod_headers.c>
<filesMatch "\\.(ico|pdf|flv|jpg|jpeg|png|gif|swf)$">
Header set Cache-Control "max-age=2592000, public"
</filesMatch>
<filesMatch "\\.(css)$">
Header set Cache-Control "max-age=604800, public"
</filesMatch>
<filesMatch "\\.(js)$">
Header set Cache-Control "max-age=216000, private"
</filesMatch>
<filesMatch "\\.(xml|txt)$">
Header set Cache-Control "max-age=216000, public, must-revalidate"
</filesMatch>
<filesMatch "\\.(html|htm|php)$">
Header set Cache-Control "max-age=1, private, must-revalidate"
</filesMatch>
</ifModule>