Siri: "You don't have the Timer app installed"

Thanks for your reply melissa_m77. Yes, my iPhone and all other devices are on the latest software versions. And yes, restarting or unpairing/repairing may very well resolve the problem.....temporarily. But doing so every few days is not a solution. I'm trying to figure out the root cause of the issue. I know Siri relies on an Internet connection for commands/requests. So I'm wondering if an intermittent loss of Internet connectivity may be the issue. Normally when there is no Internet connectivity, Siri will display a message about there being no connection to the Internet. However, in this case, Siri is responding that a specific app is not installed. So some corruption is happening with Siri or the OS where it thinks that an app is not even installed. (A quick search of the community forums shows that this also happens for other commands like when asking Siri to set an alarm...."You do not have the Alarm app installed".)