This is a broken user experience dressed up as a security feature. Hiding a protected sheet until a viewer switches to edit mode does not protect data, it hides it from the people who need to see it. That distinction matters.
The user describes a spreadsheet with two sheets: one blank, one password-protected. When viewed online, the protected sheet is invisible. Only after switching to edit mode does it appear. The password remains intact, so the viewer still cannot modify the data. But the sheet itself is hidden from view. This design choice creates confusion, not security. If the goal is to keep certain data read-only for viewers, the sheet should be visible and locked. If the goal is to keep certain data completely hidden, the sheet should be hidden deliberately, not accidentally as a side effect of the view mode. Right now, the behavior suggests a bug or a poorly understood setting, not a deliberate feature.
For anyone collaborating on spreadsheets, this has practical consequences. A team member reviewing a shared workbook sees one blank sheet and assumes the rest of the data is missing. They waste time toggling edit mode, or worse, they request access they don't need. The password protection already prevents unauthorized changes. Making the sheet invisible in view mode adds friction without adding protection. It undermines trust in the file's completeness and forces users to work around the tool instead of through it.
The solution is straightforward: set sheet visibility to "very hidden" only when you genuinely want to conceal it, and leave protected sheets visible by default. If your spreadsheet app does not offer that control, it is not serving your workflow. Users should not have to hunt for sheets. They should be able to see what is there, interact within permission boundaries, and move on. That is the baseline for a tool that claims to empower productivity. Anything less is a trap disguised as protection.