Thanks for the posts and emails in response to my ARNAV and HSI problems. It appears that the ARNAV lockup may be more or less limited to ILS approaches to MYF. I have not had the problem elsewhere; other Cirrus pilots have reported having the problem when flying the ILS into MYF.
I have learned that other Cirrus pilots have also had sticky or stuck glideslope indicators. And, as in my experience, there was no flag. In at least one case, it was noticed during the preflight deflection test. In my case the needle deflected properly in the test but stuck in flight. I will continue to tune in the localizer on both VOR receivers on all ILS approaches.