Cancelled/Rescheduled meetings not being removed from user's calendar

I have a user who will get a calendar cancellation or reschedule notice and open it. The message says that the meeting will be removed from his calendar or rescheduled to a different date, but it never happens.

This happens with both meetings scheduled in-house and meetings scheduled with other companies. I’ve verified, and other people who were on the cancellation notice have the notice removed from their calendar successfully.

I’ve refreshed the views; I’ve run fixup, updall, and compact on his mail file … I’m not sure what else to try. Can anyone point me in a certain direction for troubleshooting?

TIA.