we're facing from time to time caching issues using the news aggregation of sharepoint online hubsites. If this happens, some users with different browsers get not the actual message, for them a bit older message is shown. If the hit F5 serveral times the newest messages appaears as expected.
On Sharepoint Online there is not the root cause in my opinion. But is there any related setting on the browser like MS Edge or Chrome i could check?