Claude in Chrome: Italian Chamber of Commerce portals (dire.registroimprese.it, mypage.infocamere.it) blocked intermittently with "Navigation to this domain is not allowed"

Environment: Claude Code desktop app (Windows 11), Claude in Chrome extension 1.0.94, Chrome grants the extension <all_urls>, no Chrome enterprise policies restricting hosts, all sites allowed in the extension settings.

Problem: navigate returns "Navigation to this domain is not allowed" for the official Italian business-registry portals run by the Chambers of Commerce (InfoCamere):

• dire.registroimprese.it (filing of Business Register applications)
• mypage.infocamere.it (Telemaco, status and messages of the same applications)

On tabs already open on these domains, javascript_tool and screenshot return "Permission denied … on this domain".

The block flips over time on the same day (2026-09-25): in the morning dire.registroimprese.it was blocked and mypage.infocamere.it worked; in the afternoon it was the reverse. Reopening tabs and new tabs don't help. The same pages load fine in the Claude desktop built-in browser pane.

Impact: these are the only official channels to file and follow Business Register applications in Italy. An accounting/business-services firm uses them daily, often under deadlines set by the Chamber (e.g. 10 days to answer a correction request). The flip makes the integration unusable for this workflow.

Expected: these public-administration portals should not be blocked by domain categorization, or the user should be able to override the block for sites they explicitly approved.

Possibly related: #96068, #92464, #90928.