I found the answer to this on page 11 of FFA Advisory Circular 2023.1309-1E where they define "catastrophic" (this has the same chart as yours later on, so I think it should also apply to yours):
Notes: (1) The phrase “are expected to result” is not intended to require 100 percent certainty that the effects will always be catastrophic. Conversely, just because the effects of a given failure, or combination of failures, could conceivably be catastrophic in extreme circumstances, it is not intended to imply that the failure condition will necessarily be considered catastrophic.
The next note is also helpful:
(2) The term “catastrophic” was defined in previous versions of advisory materials as a failure condition that would prevent continued safe flight and landing.
By that reading, I think The Gimli Glider experienced catastrophic failure conditions without actually experiencing catastrophic effects, since the failure* would probably have caused catastrophic effects except that the flight got very, very, very improbably lucky.
* Total engine loss due to fuel exhaustion, in a plane that really wasn't designed for total engine loss.