This should not happen if the Pages documents were originally created by you and stored on the local drive, or on Apple's iCloud Drive. Has never happened to me over years of Pages and versions.
However, if you stored these documents on another cloud service, or network server, that may have put an encyrption, or file locking on the Pages documents that until undone, may cause Pages fits about your access.
In the Finder, click once on one of these documents that Pages believes to be locked or denying you permission. Then, following the file selection, press option+cmd+i to open a get information panel and see if the Locked category is selected. That may be something you can deselect, or it may be grayed out indicating a System lock.