Ajay Bhullar there isn't really.  It will still affect 6.6 but as the value clean-up is less aggressive it is a lot less likely to happen.  You'd probably have to have high load exercising statements something like this.  I suspect that verifying that it continues to function without issue post-fix is primarily what will have to be the validation here.

( * ) I don't want to assert that it can't possibly happen but I do think it is highly unlikely.

verified in 6.6.6-10566, using my repro in the comments w/5 threads and 61k docs i was able to see the panic one build before the fix went in, now I tried w/7 threads and 61k docs and then one more at 500k docs and did not see any panics.

Build couchbase-server-6.6.6-10571 contains query commit 69d85a4 with commit message:
MB-54393 Reset expiration when input is invalid

reopening so that we mark as resolved, so we can properly verify again with the new fix

reverified in 6.6.6-10573 using the same repro as in my earlier comment, no panics seen