Google Cloud DNS intermittently dropping - google-cloud-dns

Question

Situation:
Had registered domain via G Suite and domain synthetic records set up for gmail under another (Google) account.
Transferred the domain to a different (Google) account - gmail still working fine.
Enabled Google Cloud services for the account.
Set up a Compute Engine with fixed IP address.
Set up new Zone for the domain and Cloud DNS settings.
Reset the domain DNS to the Cloud DNS servers
Create MX records according to instructions to reinstate gmail
Created A record for root domain
Created CNAME record for WWW subdomain
At this point, gmail seems to be working fine.
However, resolution for the root domain and subdomain is intermittent - it will be up for a few minutes, then drop for a few minutes.
When its alive, I can ping the root domain. I can't ping the www subdomain at all.
The domain is 'lifetreelaw.com'
Here are the dig outputs for each:
lifetreelaw.com:
; <<>> DiG 9.11.4-3ubuntu5.3-Ubuntu <<>> lifetreelaw.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25514
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;lifetreelaw.com. IN A
;; ANSWER SECTION:
lifetreelaw.com. 325 IN A 34.66.70.41
;; Query time: 0 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Fri May 10 13:33:51 MDT 2019
;; MSG SIZE rcvd: 60
www.lifetreelaw.com:
; <<>> DiG 9.11.4-3ubuntu5.3-Ubuntu <<>> www.lifetreelaw.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 36100
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;www.lifetreelaw.com. IN A
;; Query time: 0 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Fri May 10 13:33:40 MDT 2019
;; MSG SIZE rcvd: 48
For the www subroute, dig is showing an 'A' record, not the CNAME record. I haven't set that -- is there something in the G Suite/gmail setup that would have set that? That is hanging around?
Followup
I removed the www CNAME record. This is the dig output, now:
; <<>> DiG 9.11.4-3ubuntu5.3-Ubuntu <<>> www.lifetree.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60309
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;www.lifetree.com. IN A
;; ANSWER SECTION:
www.lifetree.com. 4160 IN A 208.91.197.128
;; Query time: 4 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Fri May 10 13:50:14 MDT 2019
;; MSG SIZE rcvd: 61
It's still returning an A record, and resolving to a different IP.
Followup 2
Ok, after a period of time, the 'www' sub is not returning an 'A' record, anymore. But it's not returning a 'CNAME' record, either, even though I have it set.
Maybe I just need to wait it out.

Answer 1

Ok, waiting it out was part of the answer -- I'm just not used to a DNS name change taking so long to propagate and settle down.
The other part of the answer seemed to be flushing the DNS cache at this site:
https://developers.google.com/speed/public-dns/cache
And everything seemed to straighten out.