Hi @Federico Coppola ,
What permissions do these users have?
Due to the large throughput and the servers are shared between many sites, the cache in SharePoint Online will not last long.
So this isn't related to SharePoint cache, refer to the following article for more information on Object cache:
For your issue, please check as follows:
1) Make sure you have published your page after editing it.
2) If Content Approval is enabled in the Site Pages library, please make sure that the current page has been approved.
3) Or you have enabled Version History in site pages library, remember to release a major version or set the Draft Item Security properly.
I hope this information has been useful, please let me know if you still need assistance.
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