So what you are telling me is that your tech support is not able to figure out and tell you what and where the problem/issue/conflict is occurring with BPS and your/their particular server. Since this is not something that normally happens then there is a specific problem/issue/conflict with your/their server.
If ErrorDocument logging redirects are causing some kind of issue on your particular server then this code below would also logically be a problem for your server configuration:
1. Copy this modified code below to this BPS Root Custom Code text box: CUSTOM CODE DENY ACCESS TO PROTECTED SERVER FILES AND FOLDERS
# DENY ACCESS TO PROTECTED SERVER FILES AND FOLDERS
# Use BPS Custom Code to modify/edit/change this code and to save it permanently.
# Files and folders starting with a dot: .htaccess, .htpasswd, .errordocs, .logs
#RedirectMatch 403 \.(htaccess|htpasswd|errordocs|logs)$
2. Click the Save Root Custom Code button to save your Root custom code.
3. Go to the Security Modes page, click the Create secure.htaccess File AutoMagic button, select the Activate Root Folder BulletProof Mode Radio button and click the Activate|Deactivate button.