When configuring various DNS records you may occasionally run across
Warning: A record for this domain has whitespace but is not a "quoted string" and therefore is split into separate strings at whitespace. SPF, DKIM, and DMARC join those strings without spaces, which can cause "problems, especially for Sender Policy Framework records.
Warning: A record for this domain starts with "v=spf1" but lacks a quoted space following the '1'. This may be a badly formatted Sender Policy Framework record that will be ignored by mail software."
Unfortunately (as of Apr 2018) the support answer
offers the following example which is incorrect imho;-
v=spf1 include:_spf.google.com ~all
The correct syntax for an SPF record using Google DNS is:-
"v=spf1_" "include:_spf.google.com" "~all"
You could also review the following for more background;-