I have somewhat of a similar issue, but not with cameras.
I’ve updated the pictures in an entity card. In chrome, after a hard refresh the correct images show up, but in the HA app on android i still have the old pictures which i can’t seem to be able to refresh…
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Workaround for this is to go into the Android Settings, choose “Apps”, followed by “Manage Apps”.
There look for the Home Assistant app, select it and scroll down all the way to the bottom to choose clear data. My phone asked me to clear all data or cache only. Choosing cache fixed the issue after restarting the HA app…